Complex sentence: The aircraft for the flight was a Douglas DC-4, a four-engine propliner, registration NC88920, and had been in service since 1944, accumulating 4,146 hours of flying time.
Split into simpler sentences: The aircraft for the flight was a Douglas DC-4, a four-engine propeller-driven airliner. This particular DC-4 had a tail number of NC 88920, and had been in service since 1944, accumulating 4,146 hours of flying time.