The Defense Advanced Research Projects Agency (DARPA) in the US is planning to develop a flying submarine that can travel in and out of water at high speeds.
The "flying submarine" will be capable of flying low over the water and plunging into the sea to avoid detection, according to telegraph.co.uk.
Scientists are expected to design a submarine that is lighter than water with lift-generating wings, which can change their angle of attack allowing it to fly above and below the water.
Submarine designer Graham Hawkes said that modern lightweight carbon fibre composites could be used to build a craft that is both strong enough and light enough to fly above and below the water.
DARPA is expected to award contracts within a year for the project, which has been in development since 2008 and has reached the design proposal stage.