A GPS (Global Positioning System) aircraft guidance system for use with circular cultivated agriculture fields. The system of the present invention includes a GPS receiver adapted to determine a present position, ground track, and ground speed of an aircraft. The GPS receiver is also adapted to store a configuration of a circular cultivated agricultural field and to compute a desired flight path for achieving an optimal coverage of the field. Deviations of the aircraft from the desired flight path are also determined. The GPS receiver is further adapted to generate a dispense signal which indicates when to dispense agricultural chemicals from the aircraft. A guidance indicator is coupled to the GPS receiver for providing guidance information to the pilot. The guidance indicator is adapted to indicate the aircraft's deviation from the desired flight path and indicate whether the dispense signal is asserted. This information aids the pilot in maintaining the desired flight path and achieving the optimal coverage of the circular cultivated agricultural field.