A GNSS system in combination with a hydraulically-actuated, airborne dispenser for a dry material crop dusting system to optimize the distribution of dry materials over a particular tract of land. A GNSS subsystem is included using at least one GNSS antenna and one GNSS receiver located on the aircraft. The aircraft is equipped with an electronic/hydraulic crop dusting subsystem connected to a GNSS CPU. The GNSS ranging signals received by the antennas are processed by a receiver and processor system for determining the vehicle's position and dynamic attitude in three dimensions (3D). A graphical user interface (GUI) placed in the vehicle will give the driver a real-time view of his or her current bearing as well as a calculated “optimal path” based on calculations and variable data, such as wind speed and direction, material moisture content, altitude, air speed and other conditions. The system is adapted for operation in a differential GNSS (DGNSS) mode utilizing a base station at a fixed location.