Corsairs also served well as fighter-bombers in the Central Pacific and the Philippines. By early 1944, Marine pilots were beginning to exploit the type's considerable capabilities in the close-support role in amphibious landings. Charles Lindbergh flew Corsairs with the Marines as a civilian technical advisor for United Aircraft Corporation in order to determine how best to increase the Corsair's payload and range in the attack role and to help evaluate future viability of single- versus twin-engine fighter design for Vought. Lindbergh managed to get the F4U into the air with of bombs, with a bomb on the centerline and a bomb under each wing. In the course of such experiments, he performed strikes on Japanese positions during the battle for the Marshall Islands.