In 1955, at the request of the Fire Control Officer for the Mendocino National Forest, the Willows Flying Service in Willows developed the first operational air tanker. A Boeing Stearman 75 “Caydet” agricultural aircraft was modified at the Willows Airport with a 170 gallon tank, and this aircraft, N75081, became the first registered free fall air tanker in the history of aviation. Its first air drop was made on the Mendenhall Fire on August 12, 1955, on the Mendocino National Forest. In 1956, seven agricultural aircraft were modified to form the first operational air tanker squadron in the United States. Piloted by local aviators, the squadron operated out of the Willows Airport fighting wildfires throughout California. By 1959, heavy air tankers capable of carrying 2,000 gallons of fire retardant were proving effective in controlling wildfires, and aircraft with a retardant capacity of 3,000 gallons contributed to successful wildfire control throughout the United States.