Macchi MC.72. Fastest piston-engined seaplane ever built, one crashed killing its pilot, another blew up in mid-air, took a British fuel expert to sort out the supercharged Fiat AS.6 engine, which was two Fiat AS-5's in tandem on a common crankcase driving a contra-rotating prop. Set a world record of 441mph which has never been beaten.
I love floatplanes!
I don't know if this has been featured yet:
Polikarpov I-16. World's first single-seat, low-wing cantilever monoplane fighter with retractable undercarriage.
Designer was sent to Stalin's Gulag, for 'sabotage' over alleged slow progress in aircraft development.
Never let the politicians get involved in aircraft design.