De Havilland Mosquito: The wooden fighter-bomber that could do it all
Imperial War Museums
I'm reading Night Soldiers by Alan Furst, a WW2 espionage novel. In part 4, our hero, the Russian trained Bulgarian spy Khristo is now working for the allies. He has been parachuted into 'Czechoslovakia' and is skulking around Prague doing basic spy stuff, collecting information and radioing it up to a Mosquito flying in orbit around the city in the middle of the night at 35,000 feet. 35,000 feet? Really? Then the above video pops up on YouTube and yes, they did fly at 35,000 feet. But how did the pilots survive, not all of the Mosquitos were pressurized? Which brings us to the second video.
High Altitude Flight during WWII
390th Memorial Museum Foundation
Seems oxygen was one of the lessor problems of high altitude flight. The cold was the biggest problem.