Abstract: A digital data link is provided between an air traffic controller at a ground station and the pilot of an aircraft through digital communication between a computer on that aircraft and a ground-based computer located at the ground station and including an associated display screen containing a spatial representation of the airspace around the aircraft as well as a representation of the location of the aircraft in that airspace. A pointing device is moved to cause movement of a cursor on the display screen, beginning at the representation of the aircraft, corresponding to the movement of the aircraft that the controller intends. In response to this cursor movement, there is generated on the screen a cursorline representative of the movement of the cursor and thus of the intended path of aircraft. The ground-based computer calculates, from the beginning and the end points of the cursorline, and the length of the cursorline, the intended heading of the aircraft and the distance to be flown.