Complex sentence: Lockheed Martin Aeronautics is the prime contractor of the F-22 and was responsible for the majority of the airframe, weapon systems and final assembly; program partner Boeing Defense, Space & Security provided the wings, aft fuselage, avionics integration, and training systems.
Split into simpler sentences: Lockheed Martin Aeronautics is the prime contractor and was responsible for the majority of the airframe, weapon systems and final assembly of the F-22. Program partner Boeing Defense, Space & Security provided the wings, aft fuselage, avionics integration, and training systems.