I’ve read that “humans have survived for two years at 5,950 m (19,520 ft, 475 millibars of atmospheric pressure), which is the highest recorded permanently tolerable altitude” and that “Daulat Beg Oldie...has an airstrip at an altitude of 5065 meters (16,614 feet), which is the world's highest airstrip.” I can’t seem to find any record of the highest horizontal take-off in history. I really want to know if there is an altitude at which humans can survive but take-off is impossible. Or if there are any other conditions at which humans could survive naturally but where take-off or flight is impossible for some reason other than temperature, weather or terrain.

  • $\begingroup$ 6000m is not very high while freezing isn't that cold. I wonder why this could be a problem. If mountaineer used a drone to film the top of Everest he would break the world record? $\endgroup$ Apr 28, 2020 at 2:37
  • $\begingroup$ Are you talking about existing planes or special ones? Design studies have been carried out for planes to fly on Mars, where the air is a heck of a lot thinner and colder. $\endgroup$ Apr 28, 2020 at 17:17
  • $\begingroup$ I should have specified human cargo and not necessarily using existing aircraft. Are drones and helicopters primarily using vertical take-off instead of horizontal or am I misusing the terms? $\endgroup$
    – Y Mi
    Apr 28, 2020 at 21:45

2 Answers 2


Like most hypothetical questions of this nature, the answer is "it depends". Given enough runway at a light loading just about any aircraft with a service ceiling above 20K ought to theoretically be able to take off. One of the issues you might run into would be exceeding max tire speed.

  • $\begingroup$ Or give the plane a lot of power. FTM, NASA has built a helicopter that's intended to be flown on Mars, where the density altitude is WAY over 20K ft: mars.nasa.gov/technology/helicopter $\endgroup$
    – jamesqf
    Apr 28, 2020 at 4:37

The question of if it is possible is moot. I once asked a racecar builder what was the maximum amount of horsepower you could put in his car. His answer was, “How much money do you have?”. In other words, anything is possible with the right amount of time, resources, and desire.

In the case of your question, it is not about whether an airplane can do it. It is not even about whether a current military, cargo, passenger, jet, prop-driven, or currently produced plane can do it. It is more about where can you do it. You would need the proper facilities (long enough runway). A helicopter has already exceeded your altitude in question due to not having the runway restriction.

Didier Delsalle


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