Complex sentence: The Air Force needed a trainer with secondary combat ability that could operate from unprepared runways; being unfamiliar with such requirements, the designers provided for landing gear strong enough to make the aircraft suitable for landing on aircraft carriers.
Split into simpler sentences: The Air Force needed a trainer with secondary combat ability that could operate from unprepared runways. Not familiar with such requirements, the designers provided for landing gear strong enough to make the aircraft suitable for landing on aircraft carriers.