The trade-off of a plane built light enough to fly above 70,000
feet is that it is almost impossible to control. And 13 miles
above the ground, the atmosphere is so thin that the
“envelope” between stalling and “overspeed” — going so
fast you lose control of the plane, resulting in an unrecoverable
nose dive — is razor-thin, making minor disruptions, even
turbulence, as deadly as a missile.