Here's an airport, with some planes on the various runways/taxiways and some using the terminal ..

(airliners in green)

enter image description here

Airport/terminal design is really tricky.

There are many spatial problems which are unsolved, resulting in the incredibly inconvenient (for humans/planes) current airport paradigm.

Has an "over" terminal ever been contemplated?

enter image description here

terminal indicated in blue

enter image description here

So, the (whole) airport terminal building is simply up on stilts.

(Obviously, the clearance is high enough for the tallest existing and forseeable airliners.)

At a stroke this utterly solves two problems:

  1. Airliners never again need to reverse. They just land, drive around anywhere they want, stop under the terminal. Passengers get on and off. The airliner drives off again, drives to a runway (perhaps again passing under the terminal - no issue) and flies off.

No craft would ever reverse.

This would be a complete paradigm shift, slashing handling times, costs, personnel, machinery.

  1. The fundamental spatial problem of airports is solved at a stroke: You can land or take off anywhere, and get to and from, any gate. (Sure, you have to avoid the few pillars holding up the terminal.)

  2. From the human crowd movement viewpoint, the need for the hell of "separate terminals" is slashed or even eliminated. At worst you'd just have two or three "ranks" of these (rather like giant rows of car parking in a parking lot).

Again this would spectacularly slash the size and infrastructure costs of airport concept design. Often the whole concept of ridiculous people movers, monorails etc would be eliminated or slashed.

Note that the car freeway system would just connect to the end(s) of the terminal building. (Indeed, as usual.)

(But indeed, perhaps the blue structure could indeed include "the road itself". So the blue object represents both car driving lanes and the terminal structure, shopping, etc.)

On that: looking ahead, it's possible there could finally be a drive to your actual gate concept (if check-in / baggage handling / border functions could be rationalized), which would be an total paradigm shift in air travel.

The only technical difficulty is AeroTech or whoever would have to make a jetway that comes "down"...

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Note that it's obviously trivial to make huge civil structures "elevated",

enter image description hereenter image description here

(Indeed a civil structure for foot traffic, shops, etc is (I believe) a lighter load than a super-freeway or bridge,

enter image description here )

Ideally the supporting piers would be infrequent, allowing for totally free and easy movement of airliners, but even if the columns were between each "bay" the major paradigm shifts are achieved.

This airport paradigm would seem to be staggeringly more efficient than the current paradigm. No reversing ever! Free driving anywhere for all craft over the entire area. Wasted space slashed.

Has this ever been contemplated?

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    $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. Note: if possible, please do not add extra comments here, they can't be joined to the chat discussion anymore. $\endgroup$ – Federico Aug 16 '18 at 7:35
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    $\begingroup$ On my computer, the top images shows just airplanes and tarmac, but no terminals. Should it show terminals, like the other images do? $\endgroup$ – Wayne Conrad Aug 20 '18 at 14:36
  • $\begingroup$ I can't see that the current airport paradigm is "incredibly inconvenient", at least absent the security theater. It would seem that this design adds a number of new inconveniences, like getting wheelchairs or people with limited mobility up & down those jetways. Then too, it'd seem pretty easy to clip a wing on one of those supporting pillars. $\endgroup$ – jamesqf Aug 20 '18 at 16:06
  • $\begingroup$ "Drive to your actual gate" is a matter of fact at Berlin Tegel Airport (Terminal A) cdn4.spiegel.de/images/… - the hexagonal building with dark red jetways and planes parked around it, and cars "inside" the building is what I'm talking about. The taxi driver always asks you for the gate number if your plane departs from Terminal A and he/she will actually drop you at your gate. $\endgroup$ – ElmoVanKielmo Aug 21 '18 at 12:23
  • $\begingroup$ Fantastic info, @ElmoVanKielmo .. ah wait, is that traditional Tegel or the new airport??? $\endgroup$ – Fattie Aug 21 '18 at 12:26

Yes. An architect named Miklos Deri seems to have contemplated something similar: Drive Through Airport – Inversion of Procedures. The design is based around smaller aircraft (which reduces some of the height and size problems) and stacks aircraft together in lines to address the space efficiency issues.

Nobody has built such an airport (it's a concept, not created for any particular project), and there are practical problems associated with moving aircraft multiple times during a turnaround.

enter image description here

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  • $\begingroup$ Ah, ............ The Answer. Nice, good one! $\endgroup$ – Fattie Aug 16 '18 at 7:28
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    $\begingroup$ Damn it, that guy's renderings are much better than mine. It's funny he went with the "reduce CO2" angle to try to get funding :) $\endgroup$ – Fattie Aug 16 '18 at 7:30
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    $\begingroup$ So what happens if the first airplane in the row (or any one in front of the plane you're on) goes on a delay? Everyone behind it waits? $\endgroup$ – Sports Racer Aug 20 '18 at 19:50
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    $\begingroup$ @SportsRacer That would be another example of why nobody would build this. $\endgroup$ – Zach Lipton Aug 20 '18 at 20:10

Though I've never heard of a terminal design which allows the airplanes to pass under the passenger areas, the same problem could be solved by having the airplanes pass over the passenger area. There exist several underground airports in the world, most notably the Denver International Airport.

Though all civilian pedestrian traffic in Denver is routed above ground just like any other airport, it seems that the underground networks could serve the same purpose without many major structures above-ground. This idea could be extended into an airport with a design with advantages similar to that in the OP question, but much easier and cheaper to build and maintain.

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    $\begingroup$ How is the Denver airport underground? It has many underground tunnels and structures, like a number of airports do, but aside from conspiracy theories, aircraft are boarded other airports from above ground. $\endgroup$ – Zach Lipton Aug 16 '18 at 7:14
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    $\begingroup$ Underground is a whole lot more sensible than raising everything up. The only problem with that is user experience. But a good architect can deal with that. $\endgroup$ – MichaelK Aug 16 '18 at 8:27
  • $\begingroup$ @ZachLipton: I mention that civilians use the above-ground facilities. However, Denver sets precedent for having facilities on a different level than the ground. $\endgroup$ – 747 Aug 16 '18 at 10:05
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    $\begingroup$ Well, CDG T1 uses a similar concept, it has tunnels, and AFAIK, some of the planes don't push back but rather continue towards the main building and then above the underpasses. $\endgroup$ – yo' Aug 17 '18 at 7:32
  • $\begingroup$ It seems to be that CDGT1 is indeed the "straight through" concept (but underground rather than elevated). I had no idea about this, good one. $\endgroup$ – Fattie Aug 18 '18 at 3:32

There are several parts to your "design" that may have been implemented, though not exactly in the same way you have them in your post.

  • Building terminal structures with planes passing underneath them: one example is the bridge linking Gatwick's North Terminal to Pier 6. It allows very large planes to taxi underneath, so it is very, very high, which makes it very, very impractical (you have to go up and down very very long escalators), especially considering many passenger carry hand luggage, etc.

    The alternative in most cases is to have passengers (and luggage, and many other things) run under the taxiways rather than above them. This is what is done for "remote terminals" in most airports that have them. Here are a few examples (but the list is definitely much much longer):

    • Geneva airport: enter image description here
    • Paris Charles-de-Gaulle Terminal 1: enter image description here
    • London Heathrow Terminal 5: enter image description here
    • Hong Kong airport: enter image description here

    Note that instead of having one access from the overhead/underground structure to each plane, there are usually satellites / peers that will allow access to several planes at once.

    Depending on the actual layout and other parameters, passengers are carried between the building using moving walkways (CDG T1 and GVA in the examples above) or an automated people mover (LHR T5 and HKG in the examples above). Depending on the airport design, you may have to go down and up very long escalators as well, but given how frequent that design is over the bridge design, it must have advantages (more future-proof, larger capacity...).

  • Then there is the issue of having planes that can depart from the gate withough needing a push back. They are parked more or less parallel to the satellite, and once the jetway has been moved, they can just taxi forward.

    You can see the first two examples above (Geneva and CDG T1) apply this concept. It is not necessary very space-efficient, and is not as extreme as the design in your post, but it is definitely in use (and has been for decades).

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    $\begingroup$ My God, Gatwick has an example of this, I had no idea! Gatwick! Priceless info, thanks @jcaron (I wonder if or how they overcame the "falling small pieces of material" issue, mentioned by a commentor. $\endgroup$ – Fattie Aug 20 '18 at 14:39
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    $\begingroup$ If you are looking for structures going over taxiways, then Denver has one (though much lower, so limited to narrow-body aircraft passing beneath), and Phoenix has an APM bridge. $\endgroup$ – jcaron Aug 20 '18 at 14:53
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    $\begingroup$ Geneva looks to be the closest answer to the OP - a plane can taxi to the parking spot, then pull away on its own when it's done with all servicing. While the round structure doesn't appear to be the most space efficient, it does seem to allow for the greatest flexibility of aircraft sizes. $\endgroup$ – FreeMan Aug 20 '18 at 20:02
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    $\begingroup$ "many passenger carry hand luggage" - and at least a few use wheelchairs or other mobility aids, and they also need to be adequately provided for. $\endgroup$ – Toby Speight Aug 21 '18 at 10:45

Similar elements in airport design have been considered, but not this exact design.

New LaGuardia design

This is a rendering of a real-life plan for a renovated LaGuardia terminal. As you can see, it's not a single wide strip. Space is expensive and the design in the question results in an extremely wide airport. The picture above, if you align the planes with the taxiway/runway, achieves the same effect more space-efficiently. You can load up several planes standing behind one another, there's no need to build everything up in width.

It's actually not trivial to make large civil structures elevated. The examples in your pictures look impressive precisely because it's not trivial. Supporting spans long enough to fit large airliners, with clearances, takes some effort.

Realistically, an airport terminal like what you're proposing would have to use bridge construction methods, with the deck replaced by the terminal. Whether bridges are easier to build than tunnels, as used in Denver, varies by site, but it's fairly realistic.

Aviation is a cost-sensitive business; there's also a lot more to an airport than the passengers see that you'd have to accommodate. Bridge or tunnel style construction costs considerably more than flat boxes, so it won't become the new normal. But in well-off cities willing to spring for the airport's construction, it can be done.

  • $\begingroup$ Fantastic information, Therac. Indeed, it would appear this is the closest-to-happening version of the concept under discussion - good one. $\endgroup$ – Fattie Aug 20 '18 at 3:17
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    $\begingroup$ With the exception of the pedestrian bridge over the taxiway, I'm not sure how this fits with the "straight through" paradigm that @Fattie was asking about. I'll give it a +1, though for the "It's actually not trivial to make large civil structures elevated" comment - building even a pedestrian supporting structure high enough to clear an A380 and wide enough to clear the 80m box a plane parks in, plus some additional clearance for non-precise taxiing between supporting pillars is non-cheap. $\endgroup$ – FreeMan Aug 20 '18 at 12:57
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    $\begingroup$ Airports including Gatwick and Denver already have pedestrian bridges over taxiways. As FreeMan noted, I'm not sure how this fits with the question. $\endgroup$ – fooot Aug 20 '18 at 18:22
  • $\begingroup$ @FreeMan I should have elaborated more. The design element depicted accomplishes the purpose of the proposed design. You can have a straight-through, no-reversing movement of aircraft. But it's done with less footprint. Just line the planes up, 2xN, extend the taxiway up to a runway, or use that and the runways, and you have the result. It's simply unnecessary to reduce the queue to 1-plane-long, because gate time is on the critical path. $\endgroup$ – Therac Aug 20 '18 at 19:34
  • $\begingroup$ @Therac - I'm sorry, I'm still not following you. If the planes were "Parallel Parked" along the terminal such that a maximum nose-wheel steering angle would get them out without having to be pushed back, I could see that, but based on the image posted, I'm not seeing that happening here. I've not read your link, so maybe there's info there that is missing from the context of your answer that would clarify what I'm missing. $\endgroup$ – FreeMan Aug 20 '18 at 19:56

The main benefit you propose for the elevated terminal is that planes wouldn't have to push back from a gate, but planes pushing back really isn't a big enough problem that you'd want to build these massive amounts of infrastructure to solve it.

Returning to the original "air field" approach of having a large area where planes can move in whatever direction is most appropriate doesn't seem workable. Other answers have pointed out that ATC would become very difficult. Planes would no longer be constrained to taxiways and runways so how would you even have the conversation where a pilot says they'd like to take off, please, and the controllers direct them which way to go? In addition, you'd need to pave a truly enormous amount of land to airport runway strength, which would be phenomenally expensive. And the airport would need to be twice as long to allow planes to land, go to the terminal and take off again without turning round. Even more expensive.

It's not clear how the "straight through" concept would work with varying wind directions. What if wind conditions today mean that planes want to take off at right-angles to the terminal building? Also, even at airports where all the runways point in the same direction, it's not uncommon to change the direction of operation as the wind changes. With a "straight-through" airport, you'd have a bunch of planes pointing in the wrong direction.

The "drive to the gate" concept isn't actually new so we already know it doesn't work. Kansas City International Airport (MCI) was built that way in the early 1970s. Unfortunately, that was just before airport security screening became a thing. "Drive to the gate" fundamentally requires separate security screening at every gate, or shared between small groups of gates, which is extremely inefficient. As soon as you try to share security between larger groups of gates, you lose the "drive to gate" concept because (a) the security area is used by many people, so there's not enough parking space nearby; (b) it's shared between a lot of gates, so there's not enough space for all those gates to be nearby; so you end up driving to somewhere quite far from security which is, itself, quite far from the gate. Basically, you're back to the traditional airport design. When MCI was built, TWA insisted on the "drive to gate" format, it was found to be awful within a couple of years, TWA insisted that the airport be rebuilt, the city said "Sorry, dudes, but we just spent an absolute fortune building this thing to your design; we can't afford to do it all again" and TWA said, "Screw you, we're moving to St Louis."

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    $\begingroup$ Great example about MCI ... $\endgroup$ – Fattie Jan 9 '19 at 17:42
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    $\begingroup$ DFW has a similar design to MCI, and it's one of the busiest airports in the world, so it's not fatal. However, the "thin" design is clearly not as efficient as piers (see DEN, ATL or PHX-T4) when used as a hub (mostly connections), which wasn't really a thing yet back when DFW was designed. $\endgroup$ – StephenS Jan 9 '19 at 19:00
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    $\begingroup$ @StephenS DFW looks more like "drive to a pretty small terminal" than the literal "drive to gate" of MCI. $\endgroup$ – David Richerby Jan 9 '19 at 19:12
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    $\begingroup$ @DavidRicherby At DFW A/B/C/E, the parking slots are labeled by what gate you're across from because, before security checkpoints were retrofitted, you'd park at your gate number and walk straight through the (very thin and open) terminal to your gate. DFW D (much newer) was designed from the start to funnel everyone through one big security checkpoint; there are no gate numbers in its parking garage. $\endgroup$ – StephenS Jan 9 '19 at 20:03
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    $\begingroup$ Parts of MCI are still a narrow miserable widely-disliked mess thanks to these design decisions and the retrofits to add centralized security. $\endgroup$ – Zach Lipton Jan 9 '19 at 22:38

To answer the question: No, this concept has never been considered, at least not seriously. The reason for this is

You can land or take off anywhere, and get to and from, any gate.

This would create a nightmare for anyone planning arrivals and departures, and is sure to result in utter chaos (not to mention crashing planes).

However, as some has noted parts of this concept has been used. Overhanging gates, walkways, terminals and so on. What you have described in your suggestion is basically (to my understanding) piers as used on airports today, although with a different shape than we are currently used to.

(...) the need for the hell of "separate terminals" is slashed or even eliminated. At worst you'd just have two or three "ranks" of these (rather like giant rows of car parking in a parking lot).

These are piers. An airport holds a lot of people during peak hours. Not everyone is on their way to an aircraft ready to board, not everyone is collecting their luggage and driving off. A lot of people are early, transiting between flights, delayed or there for other reasons. Having a large terminal helps with the crowding, as the people can be spread out over a larger area. Piers can then be built with a smaller capacity in mind, as you keep the number of shops and dining areas to a minimum to avoid attracting people who have to wait for whatever reason.

They just land, drive around anywhere they want, stop under the terminal. Passengers get on and off

Again, this would be chaotic. Passengers need to know where the plane will arrive. The ground controllers has to know so they can coordinate the planes movement with any other plane on the ground, ground services (food, fuel, cleaning) needs to plan how much to deliver and where, plus the fact that different aircraft require different infrastructure on the ground.

An A380 carries more people than an E-170. Allowing the pilots to just select a gate might result in an A380 arriving only to find that their gates are occupied by smaller aircraft. If they are at all able to get into a smaller gate and unload, the areas around that gate might not have room for the embarking and disembarking passengers, leading to congestion and delays.

This airport paradigm would seem to be staggeringly more efficient than the current paradigm. No reversing ever! Free driving anywhere for all craft over the entire area. Wasted space slashed.

There are many factors in play when designing an airport. Cost and complexity are two, but regardless of how efficient you might create the airport you are still faced with the fact that you need to schedule movements. People will always be dumb, slow, confused and unfamiliar with your airport and airplanes will always be delayed or suffer breakdowns, and your facilities need to account for this. Your concept might work if everything else was working perfectly/to schedule, but I fear that once a disruption occur it would propagate and gradually cause more and more problems.

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    $\begingroup$ I'm not sure that OP intended for the pilot to pick a gate as you & I do a parking spot at a car-park. However, having one, miles long terminal would be an absolute nightmare for the passengers arriving from the parking lot at one end and needing to board an aircraft at the other end. It would be bad enough if the car parking access were in the middle of the terminal. Not to mention trying to make a connection from an arrival at one end and a departure near the other end. $\endgroup$ – FreeMan Aug 20 '18 at 13:01

Amsterdam's Schiphol Airport sort of uses this property, but the planes don't end up underneath the terminal. Rather, the ground underneath the terminal is used for vehicle traffic and whatnot. When you get off the plane, you get picked up by a bus and brought to an area where there is an escalator/elevator to bring you up to the terminal level.

I reckon airports don't want to use your design because a chunk of building material could cause expensive damage to an aircraft, even if the chunk was the size of a grape.

  • $\begingroup$ that's a good point about falling material - good one $\endgroup$ – Fattie Aug 20 '18 at 3:20
  • $\begingroup$ The reverse is also true - a damaged aircraft could easily cause flames to damage the building above. $\endgroup$ – Wossname Jan 10 '19 at 15:00

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