Major (later Colonel) John W. Oswalt entered Army Aviation in Class P-2 at Fort Sill, OK, in mid-1942, and was one of the first ten L-Pilots to be sent to a WW II combat zone, landing in Morocco with General Patton's Western Task Force in November, 1942. Amassing 1,013 hours of combat flying time as Aviation Officer of the 1st Armored Division, he fought in the North African and Italian campaigns, including Cassino and Anzio.

During 1942-1943, when the concept of the organic Air Observation Post was on trial, Oswalt helped to prove its success beyond doubt, providing combat proven tactics and concepts to the Aviation School. Primary guidance was furnished in many new areas of operations, including deep aerial night adjustments of artillery fire and the justification for and use of L-5 Stinson aircraft for flight over mountainous terrain, the first equipment advancement over the L-4 Piper Cub.

During the breakout from Anzio and drive north to Rome, fast-moving U.S. armored columns were attacked by our own fighter-bombers. Responding quickly, Major Oswalt installed VHF radios in two L-5's, painting the top of the wings with their call signs, "Horsefly Yellow" and "Horsefly Red," the first instance in which Air Corps fighter strikes were directed from light Army aircraft. From this beginning, later day "Mosquito Mission" or FAC flights were developed.

Due to his wide combat experience and record of innovation, Major Oswalt became Aviation Officer of the 15th Army Group, serving under its commander, General Mark W. Clark, until 1948.

In 1949, Oswalt organized the groundwork in several major Army Aviation Research & Development areas. Through his leadership and direct efforts while serving with Army Field Forces at Fort Monroe, VA, Oswalt initiated actions to obtain the first L-20 and L-23 aircraft and several of the Army's early cargo helicopter models.