Ah yes, I thought, scrolling past the Learjet 45, the de Havilland Vampire, the Caproni Ca.161, all high-tech jet aircraft of the space age... hang on, the Ca.161?! I must say I'm sceptical that such a single-engined biplane could reach 50000 feet. The most advanced piston-powered aircraft, the four-engined Lockheed L-1649 Starliner, had a cruising altitude of no more than 30000 feet.