The Army returned its five C-75s to TWA in 1944, which sent them back to Boeing for rebuilding. Boeing replaced the wings and horizontal tail with those from the B-17G, while more powerful engines were fitted and the electrical system was replaced with one based on the B-29 Superfortress. Passenger capacity was increased from 33 to 38. The total rebuilding cost to TWA was $2 million; the five aircraft re-entered passenger service on April 1, 1945. Although TWA was committed to the larger and faster Lockheed Constellation, it kept the Stratoliners until April 1951.