The RFB X-114 Aerofoil Craft was an experimental ground effect vehicle intended to work over water, with the ability to fly out of ground effect when required. It was the last of three such aircraft designed by Alexander Lippisch in the 1960s and early 1970s. The low powered, two seat proof of concept Collins X-112 was followed by the RFB X-113, structurally and aerodynamically refined but still low powered.

All three were inverse delta aircraft, that is they had a wing which was triangular in plan but with a straight, unswept leading edge. Combined with strong anhedral, this layout produces stable flight in ground effect. Specifically, it is claimed that it is stable in pitch and also that it can fly in ground effect at altitudes up to about 50% of its span, allowing it to operate over rough water.