Aircraft are usually provided with moveable aerofoils as a means to control direction and orientation. On fixed wing craft these commonly take the form of hinged vanes or ailerons. In Coanda craft the vanes are usually hinged to the skirt of the canopy. The invention offers an alternative method of steering in which the aerofoil is flexible and that the craft has means to cause the aerofoil to flex. Applied to a Coanda craft, the canopy (1) of the craft can be made to be flexible and the craft comprise means (4, 5, 6) to flex selected portion of the canopy so as to cause the craft to pitch or roll. The airfoil (1) may be formed from a single integral piece and be composed of a composite material having a varying composition so as to give different portions of the aerofoil different levels of flexibility.