The 431st was specifically trained to provide long-range escort for bombers during daylight raids on Japanese airfields and strongholds in the Netherlands East Indies and the Bismarck Archipelago.

After moving to Biak in July 1944, the squadron flew escort missions and fighter sweeps to the southern Philippines, Celebes, Halmahera, and Borneo.

Moved to Zaragoza Air Base, Spain in September 1958 where new Convair F-102A Delta Dagger interceptors replaced the F-86D's.

Inactivated in 1964 with withdrawal of B-47 Stratojet from inventory and SAC turning jurisdiction of its Spanish refueling bases to USAFE.

Equipped with F-4C Phantom II tactical fighter-bomber, engaged in training, participated in numerous exercises, operational readiness inspections, deployments.

In February 1966, the squadron began McDonnell F-4D Phantom II replacement pilot training for personnel to be deployed to Southeast Asia.

McClellan was the Air Force Logistics Command prime support depot for the F-111 and changes and modifications could be made there and tested by the detachment.

The 431st's mission was to test and evaluate Time Compliance Technical Order modifications to the F-111A/D/E and F models prior to those changes being released to operational F-111 tactical wings in the United States and Europe.

In addition was tasked with exploiting foreign technologies, and developing leading-edge tactics to improve the future combat capability of aerospace forces.