Actually when they were working on the Warthog they consulted with the top German Stuka pilot, who was still alive at the time.
A-10 designer Pierre Sprey:
“I felt that the combat specifics, such as tactics, targets, aerial cannon effectiveness, austere field operations, surge sortie rates, air-ground communications and coordination, of the World War II close support experience were so relevant to designing a first-rate CAS [close air support] plane that I required every member of the A-X concept design team to read Hans-Ulrich Rudel’s Stuka Pilot.”
Hans Eric Rudel, one of Der Furher’s great favourites.