Could an angled flight deck have become practical before the arrival of jets?
Short answerYes. Fast twin-engine aircraft with high landing speeds could have created the need before jets.
NotesThe operational reason for an angled deck is landing speed and the danger of a failed approach, not jet propulsion by itself. Fast twin-engine piston types such as naval Mosquito or Sea Hornet developments would have made straight-deck recovery increasingly hazardous. An angled landing path lets an aircraft go around instead of running into a parked deck group. Those piston-aircraft demands could therefore have encouraged the layout before jets became dominant.