The ten pre-production gliders were eventually delivered by the end of 1942, and the first production glider was put together between March and April 1943. Production of parts and the building of complete gliders continued throughout 1943, but production schedules continued to fall behind, particularly when the United States Army Air Forces became interested in the glider, requiring a significant number to be completed for Operation Overlord, the airborne landings in Normandy, and a number of others to be used in the Far East. This placed further pressure on GAL and the Hamilcar Production Group, as the USAAF demands would require further production and new flight trials to see if the glider would operate effectively in a tropical climate. In late 1943 the USAAF required 140 Hamilcars, which would be used to transport bulldozers and other construction equipment for airfield building, and in November it was agreed that 50 would be supplied to them by June 1944. However, the continued slow production of the gliders so concerned the USAAF that it cancelled its requirement in February 1944; this meant that American personnel who had been helping with the production of the gliders were withdrawn and production times were further delayed. It also meant that only British airborne forces would use the Hamilcar. By January 1944 only 27 Hamilcars had been erected and were ready for use; a total of 53 had been produced, but the rest were in storage awaiting parts to complete them or to be erected. Finding personnel to erect the gliders, and airfields to store them, continued to be a problem. By June, however, eighty of the gliders had been manufactured and erected and were ready for use in airborne operations, in time for a small number to be used during Operation Tonga, the British airborne landings in Normandy. Production continued throughout the conflict and finally ended in 1946, with a total of 344 being produced.