"Tamas Feher" wrote in message
...
Yes, they can fly in the air and underwater

There was some protoype USAF delta-wing jet in the early 50s that landed
on waterskid and then acted as a submarine down to 15 meters of water.

See: Convair XF2Y Sea Dart



Partly right, any Sea Dart submersions were unintentional and
going down 15 metres was a one shot trick


Keith