Complex sentence: The Payen Pa 49 Katy was a small experimental French turbojet powered delta wing aircraft, first flown in 1954, was the first French aircraft of this kind and the smallest jet aircraft of its day.
Split into simpler sentences: The Payen Pa 49 Katy was a small experimental French turbojet powered delta wing aircraft, first flown in 1954. It was the first French aircraft of this kind and the smallest jet aircraft of its day.