We got you so good at flying through air, we wanted to take it away and see what you do.

All your experience is in air, so ignore all your prior experience. Also, without this prior experience you would be unqualified.

So wings... don't need them.

Before, you flew the skies with advanced methods of compressing air and expelling it, forcing changes of pressure around you, and playing on two competing physics principles by Newton and Bernulli. Now you just fly by pushing on explosions.

In an airplane, if it stops working you can just glide to the ground. In a spacecraft, if it stops working there is no ground...

If anyone wants to know; it does have to do with handling stresses of flying and orientation in space, but it really has to do with dedication to the job and the skills of rigorously learning procedures and systems and applying the correct responses to situations.

Also, you have to go through sky 1 to get to sky 2, and when you're done you go back through sky 1.

But, while you're in sky 2, almost nothing you used in sky 1 is relevant. Lift? Gone. Drag? Nearly zero. Thrust? Turned off once you passed sky 1. Rudder, elevators, ailerons, flaps, slats, airbrakes: sorry, no. Altimeter? Irrelevant. Airspeed? Off the charts. Vertical speed indicator? Mostly zero, but not something you need to watch. Artificial Horizon? You don't really need that. Air traffic control? Airways? VORs? Left behind in sky 1.

I wonder if they've ever considered training submariners as astronauts. Living inside a vessel under massive pressure is obviously different in some ways from living under one in zero pressure. But, both involve a pressure differential that can kill you. You're cut off from the world. You're breathing recycled air and drinking recycled water. You're away for months at a time. You're living in a small enclosed space with other people. Things with tentacles are creeping nearby...