Simplify the following text for a Grade 5 native English-speaking person.
Original: Prior to becoming an astronaut , he had attended the United States Military Academy , and from there he joined the United States Air Force and flew F-86s at Chambley-Bussieres Air Base , France .
Simplified: After training he joined the United States Air Force . He flew F-86s at Chambley-Bussieres Air Base , France .