The Manta Fighter was a literal "flying sub" that could function as a high-performance fighter in the air and a zippy torpedo-firing attack submarine underwater. The plane's propellers would shift from the front to the back of their nacelles to accommodate the change from an atmospheric to liquid environment.
The Mantas were flown off gigantic flying aircraft carriers under command of the British Royal Navy. Pilots wore big bubble-headed helmets and pressurized flight suits that allowed them to survive should their planes be compromised while underwater.
A 32 piece 1:72 resin scale model kit of the Manta was briefly available from Fantastic Plastic.[1]