Complex sentence: In the immediate postwar era, Quill continued as a test pilot, flying the latest Supermarine jets including the Attacker and Swift; he later became a military aircraft marketing executive for the British Aircraft Corporation.
Split into simpler sentences: In the immediate postwar era, Quill continued as a test pilot, flying the latest Supermarine jets including the Attacker and Swift. Later he became a military aircraft marketing executive for the British Aircraft Corporation.