Can you actually open an airplane door mid flight?
But even then it would still require significant strength, as there would likely be some air differential due to the aircraft's speed/air pressure against the door.
At higher altitudes it is essentially impossible for a human. You'd have to blow apart the door or equivalent.
The biggest thing is the pressure differential. And that varies based on speed/altitude/etc. At normal cruise in a jet aircraft, it just isn't happening.