This paper presents an interface that allows a human pilot to remotely teleoperate an unmanned aircraft flying at a fixed altitude with input only from an electroen-cephalograph (EEG), which is used in this case to distinguish between left- and right-hand motor imagery in the brain. The approach is to construct an ordered symbolic language for smooth planar curves and to use these curves as desired paths for the aircraft. The underlying problem is then to design a communication protocol by which the pilot can, with vanishing error probability, specify a string in this language using a sequence of bits sent through a binary symmetric channel in the presence of noiseless feedback. Such a protocol is provided by the combination of arithmetic coding as a method of lossless data compression with posterior matching as a capacity-achieving channel code. Preliminary hardware experiments demonstrate the feasibility of this approach.