Minimum number of runways required for international airports?

What is the minimum number of runways required for an International Airport to be operational - commercial aviation?

Would two runways suffice?

• I'm not sure if it makes any difference, but you might want to add a jurisdiction (e.g. US/FAA, Europe).
– user12873
Nov 24, 2021 at 4:33
• How do you define "runway"? For example, the same strip of pavement is typically used in both directions (and thus has two runway designations, e.g. "01" and "19") and is also typically used for both landings and departures in both directions. But if you have, for example, a single strip of pavement that can only be used in one direction, or that can only be used for landing, does that count as a half runway? What about airports for floatplanes, if the planes simply land and depart on a lake into whatever direction the wind happens to be coming from, does that count as zero runways, infinite Nov 24, 2021 at 16:51
• … runways, or as one runway that is constantly moving around? Nov 24, 2021 at 16:51
• "International" doesn't mean "big airport", it means "airport with customs facilities". Eckhart International consists of a thousand-meter grass strip and a windsock, but is just a five-minute walk from the nearest US Customs station.
– Mark
Nov 24, 2021 at 21:19
• Can it be an international heliport with 0 ?
– h22
Nov 26, 2021 at 18:39

Instead of just looking at the minimum number of runways, I though it would be interesting to have a look at the overall statistics for the number of runways. So I went through my navigation database (AIRAC 2111) and filtered for international airports based on Wikipedia's list. The following histogram shows the number of runways for the 1356 international airports in my database (click image for higher resolution):

As you can see, most international airports (921) actually only have a single runway. The following plot shows the same histogram with a logarithmic y-axis:

There is one international airport with 7 (KDFW) and one with 8 (KORD) runways. The following plot shows a pie chart of the number of runways:

About 2/3 international airports only have a single runway. Less than 1% have more than 4.

• The wiki list of international airports is very lacking for the US. It appears to only include major airports. Small ones like Ogdensburg International Airport are not there, even Niagara Falls International Airport which has 3 runways isn't on there. Nov 24, 2021 at 15:35
• @rtaft I agree, it's not a great list. Wikipedia even has a warning about original research on the page. It's difficult to find a good list with global coverage, which is also computer readable (the Wikipedia list contains IATA codes). For the US, there is 14 CFR § 122.13, but not computer readable... Nov 24, 2021 at 15:51
• Worth to mention that international airport doesn't mean huge airport or long runways. Might not be true in the US but in Europe where all the countries aren't that far away from each other. A graph showing the runway's length could have been relevant. I believe the number of runways depend on the traffic. Nov 24, 2021 at 23:56
• @Alexis A log-axis doesn't need meaning. It's purpose is to show both large and small values at the same time. On the linear scale you cannot even see the bar for 7 and 8 runways. Nov 25, 2021 at 8:40
• In case of an airport exclusively served by helicopters, airships etc. zero runways will probably do. A negative number of runways might be legal, but is difficult to explain. So I guess it is safe to say that zero is the minimum number required. Nov 25, 2021 at 16:21

Minimum number of runways required for international airports?

There is no such requirement for an international airport, so the strict answer is zero landing area, and the practical one is one landing area, which can be a landing strip or an helipad.

Would two runways suffice?

In fact most international airports have only one landing strip because this is not possible or not justified to build and maintain more. This landing strip can be used in both directions (creating two runways), and both for landing and takeoff. A strip may be constrained in one direction, for landing and/or takeoff due to obstacles preventing adequate clearance or environmental reasons.

On the other hand, what actually defines an international airport is the ability to legally support cross-border flights. International airport are first different in the sense they must have customs controls.

From the aeronautical information for Tahiti International Airport (NTAA) we see it's a single strip airport. Note customs availability in the services section:

International strictly refers to customs services availability

• For aviation matters, including in the US, an international airport is an airport which can be used for international flights, as opposed to domestic flights only. International flights are flights crossing the State borders.

• Accordingly an international airport is one which can deal with customs and quarantine matters for arriving and departing persons and shipments.

• Is an airport, i.e. it deals with air travel, having a IATA code, a destination code in commercial booking systems, is not required nor sufficient to define an airport,
• Provides customs and quarantine services to allow persons and goods to lawfully enter or leave the country.
• Is not defined by the number of its runways, helipads or waterways, and therefore can have only one of them is that makes sense for the airport manager.

Formal definitions for international airport are detailed below if you are interested.

ICAO definition

ICAO is the UN body facilitating civil aviation across borders. State regulators usually subscribe to ICAO work. ICAO definition of an international airport:

Any airport designated by an ICAO Contracting State in whose territory it is situated as an airport of entry and departure for international air traffic, where the formalities such as customs, immigration, public health, agricultural quarantine and similar procedures are carried out.

Source ICAO glossary

FAA definition

FAA subscribes to ICAO definition, adding details:

Relating to international flight, it means:

• An airport of entry which has been designated by the Secretary of Treasury or Commissioner of Customs as an international airport for customs service.
• A landing rights airport at which specific permission to land must be obtained from customs authorities in advance of contemplated use.
• Airports designated under the Convention on International Civil Aviation as an airport for use by international commercial air transport and/or international general aviation.
(See ICAO term INTERNATIONAL AIRPORT.)

International airports typology

Many international airports are located on touristic islands and most of them have only one landing strip (which can be used in one or both direction, creating one or two runways).

Princess Juliana International Airport (TNCM) is a good example of such medium sized airport with customs and only one landing strip:

KLM Boeing 747 taking off from TNCM, source

Another element for promoting an airport to international status has been mentioned by @rtaft in a comment:

There are many small international airports along the US Canadian border that only deal with small aircraft flights between the two countries, as well as some along the Mexican border for Mexican flights.

The decision to build a second strip is usually driven either by the existence of strong cross winds or the volume of operations.

• +1 only answer that mentions Customs! There are many small international airports along the US Canadian boarder that only deal with small aircraft flights between the 2 countries as well as some along the Mexican boarder for Mexican flights. Nov 24, 2021 at 14:23
• @rtaft: I'm adding this information into the answer if you don't mind. Good point.
– mins
Nov 24, 2021 at 14:28
• thanks. I heard they were quite busy during covid. Snowbirds were allowed to fly over using these small international airports when the border was closed, then pay a service to transport their vehicles, RVs, etc, across to the airport to get around the closed border restrictions. Nov 24, 2021 at 14:47
• Other important factors for the runway numbers are space and money. TNCM is a great example: Where would you put a second rundway on that island (given you have enough traffic). On the other hand, if you have no space but money, you just build a new airport, maybe even filling up some ocean. Nov 25, 2021 at 7:18

In Germany, Lufthansa (the German flagship airline) and Deutsche Bahn (German railways) have a cooperation, where some Deutsche Bahn trains also have a Lufthansa flight number and Lufthansa sells airline tickets for those trains. As a result, some German train stations have an IATA airport code. And at last at some of them, I believe you can have your luggage checked through all the way onto the train and go through customs at the arrival train station.

So, that would technically be an International Airport with zero runways and no aircraft movements.

• Technically IATA codes are travel destinations, not airports. It happens most IATA codes can be matched to ICAO airport designators, or to other destinations like Disneyland, but such destinations are not airports, don't have airport designators, and are not subject to air regulations.
– mins
Nov 24, 2021 at 17:29
• This does not make tha train stations airports in any way, not even some paper theoretical one. If some booking website shows them among airports, it is just a limitation of that website, nothing more. Nov 25, 2021 at 8:16
• @mins DLP does not appear to be an official IATA location code. Beware the wide variety of unsourced lists online claiming to be IATA codes but actually containing unofficial placeholders used in various systems. Nov 25, 2021 at 16:21

Serious answer: one, Bianfable is correct.

Slightly less serious answer: zero. In principle, there are scheduled flights from CHX (Vancouver Harbour) or YWH (Victoria Harbour) to LKE (Seattle Lake Union), all three of which of which solely operate seaplanes and have no "runways" in the normal sense of the word.

(I say "in principle": it appears that at the time of writing the scheduled routes have been suspended. But that will presumably lift, eventually.)

There are a few other Canadian airports with only seaplane facilities that are classed as ports of entry by the Canadian authorities, and thus could in principle have international travel, eg Whitehorse or Seal Cove, but Victoria & Vancouver Harbours seem to be the only two pure-seaplane sites with a (normally) scheduled service.

In the Caribbean, there are scheduled services from the US to NSB (North Bimini, Bahamas), which is a purely seaplane site. (The US end seems to be Fort Lauderdale, which is definitely not.)

• Whether there is a scheduled service does not matter, whether there is customs does. But if the scheduled service is international (which it is for the last case), there has to be customs as well. Nov 25, 2021 at 16:06
• @JanHudec in the Canadian case these are explicitly designated as "ports of entry" by the border authorities, which I would interpret as covering customs. The US and Bahamas ones are less clear, but I would agree that if there's a scheduled international service there must be something. Nov 25, 2021 at 16:47
• Is there US customs preclearance at the British Columbia seaplane facilities? If so, the US facility may lack customs facilities of its own. Nov 26, 2021 at 12:50

San Diego International Airport (SAN), in San Diego, CA is one of the world's busiest single runway airports. Interestingly, Montgomery-Gibbs Executive Airport, also located in San Diego, is not an international airport, and has 3 runways. It is one of the world's busiest GA airports.

So, 1 runway would be the minimum for an international airport.

• Never knew that about Montgomery field - it's the 1 airfield in SD ive flown out of.
– Jamiec
Nov 24, 2021 at 9:10
• Don’t know if it’s the worlds busiest GA airport. I would guess Van Nuys or Daytona would give them a run for their money. Nov 24, 2021 at 15:07
• 1 runway is the minimum for any airport, even it its a grass paddock :) Then again, if the area is large enough, that might class as infinite runways cos you could land in any direction? Nov 24, 2021 at 21:36
• It's quite disputable that it's the world's busiest. Xiamen Gaoqi International Airport and London Stansted both had more passengers than SAN and they're definitely single-runway. London Gatwick has even more, but one could argue it's technically not single runway. Nov 25, 2021 at 0:29
• @Criggie: You can operate helicopter or other VTOL flights without any runway at all... ;-) Nov 25, 2021 at 1:14

Ketchikan International Airport in the State of Alaska, USA has one runway.

http://www.airnav.com/airport/PAKT

Consider London airports:

• Heathrow (LHR): 2 runways
• Gatwick (LGW): 1 runway (there's technically a second runway, but it's so close to the first one they can't both be used at the same time)
• City (LCY): 1 runway (and a very short one with a steep approach!)
• Luton (LTN): 1 runway
• Stansted (STN): 1 runway
• Southend (SEN): 1 runway

They are all international airports. Gatwick is consistently in the top 15 airports ranked by international passenger traffic.

• If if they are close, they are still 2 runways. Many airports that have multiple runways have them crossing each other and they cannot be ised simultaneosly. They are still airports with multiple runways. Nov 25, 2021 at 8:21
• @VladimirF what? It's 6 different airports. Nov 26, 2021 at 15:19
• @Polygorial Vladimir is talking about Gatwick which is a pretty weird airport which has 2 runways but is nearly universally considered as having only one due to their layout. Nov 26, 2021 at 15:28
• @jcaron thanks, now I understand the comment :-) Nov 26, 2021 at 15:30

As an example of a small international airport have a look at Saint Helena Airport, The World's Most Useful Airport. All flights are international, the record amount of passengers were in 2019 with about 8.500 passengers. Not all international airports are big.