Complex sentence: After WWII, it began developing a series of trainers for the French Air Force; its SIPA S-200 Minijet, first flown in 1952, was the world's first all-metal two-seat light jet.
Split into simpler sentences: After WWII, it began developing a series of trainers for the French Air Force. Its SIPA S-200 Minijet, first flown in 1952, was the world's first all-metal two-seat light jet.