But how many aircraft will continue flying at 50 kts in a 45 degree
bank? Not many, I'd wager...

I wouldn't make any bets on that. Since you used the word "aircraft" which
includes gliders and not "airplane", the answer is tens of thousands of
gliders will do that.

Typically, ~25% of a gliders flight time will be flown in a 45 degree bank
circling in thermals. The rest will be in 'high' (100 Kts) speed cruise
between thermals. My Nimbus will fly quite happily in a 45 degree bank at
40 Kts while sinking 120 FPM. That circle is 300 feet in diameter.

Turning back to the departure runway from 200 feet AGL will leave the glider
WAY above glidepath requiring heavy airbrake use to avoid overshooting the
runway.

In straight flight, my Nimbus doesn't so much stall as it just flies so slow
that the controls lose their grip on the air. The big wing just keeps
flying.

Bill Daniels