Complex sentence: The T-37 served as the U.S. Air Force's primary pilot training students for over 52 years after its first flight before moving on to other advanced Navy, Marine Corps or Allied trainers.
Split into simpler sentences: The T-37 served as the U.S. Air Force's primary pilot training vehicle for over 52 years after its first flight. After completing Primary in the Tweet, students moved on to other advanced Navy, Marine Corps or Allied trainers.