Try to get his separation papers from the service, which should show his service areas and missions. For WWII air pilots try the Army. Pilots were usually either Navy or Army Air Corps members at this time. Cargo pilots tended to be Army (except the women who were a separate service group altogether).
I checked for his name online at NARA in the AAD database at www.archives.gov/ but could only find a similar name from South Dakota, for Ironcloud, Samuel P.