Complex sentence: The existing Air Transport Command was redesignated Troop Carrier Command, and was specifically given the mission for providing transportation for parachute troops, airborne infantry, and glider units; and for conducting local air transport services within the theaters of operations.
Split into simpler sentences: The existing Air Transport Command was redesignated Troop Carrier Command. It was specifically given the mission for providing transportation for parachute troops, airborne infantry, and glider units; and for conducting local air transport services within the theaters of operations.