Despite military usage of HALO and HAHO high altitude parachute techniques (25-30,000 ft) since the vietnam war, very few civilians have ever made the leap. Ass

Despite military usage of HALO and HAHO high altitude parachute techniques (25-30,000 ft) since the vietnam war, very few civilians have ever made the leap. Assuming you could actually get out of a pressurized cabin, you'd almost certainly blackout from hypoxia before you opened your chute and you'd turn into a popsicle from sub-zero temps. HALO jumpers breathe pure oxygen onboard and jump with oxygen tanks. A single breathe during the transfer is enough to return your nitrogen levels to normal and cause blackout on egress. Any kind of medical condition, even anxiety or exhaustion can dramatically affect your susceptibility to hypoxia and normal clothes would not save you from frostbite. By the way, 747's cruise at up to 40k altitude and 565mph. Jumping out is not a good idea.