Pathfinders were developed following the Allied invasion of Sicily in 1943. After the widespread airborne drops there, commanders sought a way to organize and deliver airborne troops more accurately. The job fell to Colonel Joel Crouch of the Army Air Forces and Captain John Norton of the 82nd Airborne Division. Based at Biscari Airfield in Sicily, these men originated pathfinder tactics.
In the first drops in the invasion of Italy, pathfinders used colored lights, smoke pots, and vision panels to designate drop zones. These teams also used radio communication and a simple radar homing system consisting of two components, "Eureka" and "Rebecca," to aid in aircraft navigation. Once a ground team was positioned, it would set up radios and activate the radar transmitter, the Eureka set. The Rebecca device in the planes would home in on the signal produced by the ground team and use it to pinpoint the exact location for the drop. Pathfinder units were composed of a large squad of 9–14 men for signaling with 2 Eureka sets and 9 Halifane (illuminating) lights and a 5-man security team. Squad members were volunteers from airborne units such as the 82nd and 101st Airborne Divisions. Pathfinders jumped in such missions as Operations overlord, marketgarden, and varsity. After World War II, pathfinder techniques continued to undergo refinement.
The term pathfinder was also applied in strategic bombing. After the Luftwaffe employed a specially trained force to mark and illuminate targets during the Battle of Britain, the Royal Air Force formed a similar group for the strategic bombing of Germany. Special squadrons of highly trained crews flying Wellington and Stirling bombers (later mostly Mosquito bombers) flew in advance of the main bomber stream to mark targets for the less-experienced bombers crews following them. Pathfinders were also used to mark the route to the target, and a senior pathfinder known as the master bomber or master of ceremonies would fly above the target and provide advice to the main bomber force by radio.
Blair, Clay. Ridgway's Paratroopers: The American Airborne in World War II. New York: Simon and Schuster, 1985.; Booth, T. Michael, and Duncan Spencer. Paratrooper: The Life of Gen. James M. Gavin. New York: Simon and Schuster, 1994.