A U.S. Army L-4 Grasshopper liaison aircraft sits on a rough dirt airstrip during the Luzon campaign in the Philippines, 1945. These lightweight, unarmed observation planes -- adapted from the civilian Piper Cub -- flew low and slow over the battlefield, allowing artillery spotters to direct fire onto enemy positions and commanders to survey terrain, all while operating from primitive forward airstrips close to the front lines. Project: 218438