The Lockheed C-69 Constellation is a four-engined, propeller-driven military transport aircraft developed during World War II.

It first flew in 1943, and production of the 22 constructed was shared between the United States Army Air Forces (15) and commercial carriers.

Along with the assembly lines, the Lockheed L-049 Constellation airliner was also requisitioned and redesignated C-69 and was to be used as an equipment and personnel transport by the United States Army Air Forces (USAAF).

In February 1942, the 80 L-049/L-149 Constellations ordered by Transcontinental & Western Air and Pan American World Airways were also requisitioned.

For the occasion, Lockheed had borrowed the Boeing Aircraft Company's chief test pilot, Edmund Allen.

On July 28, 1943, the XC-69 was symbolically handed over to the USAAF at Las Vegas, Nevada and given a military serial number 43-10309.

[2] Major problems, however, surfaced with the R-3350 powerplant that powered the C-69, when an XB-29 test aircraft crashed into a Boeing factory.

This happened to the point where Lockheed started to doubt the abilities of the engine's manufacturer, Curtiss-Wright.

Lockheed continued to focus on building combat aircraft while the C-54 Skymaster, the C-69's competitor was already flying and officially ordered.

Lockheed had hoped to produce four C-69 aircraft by the end of 1943, but due to the low importance of the C-69 to the USAAF, this didn't occur.

On April 16, 1944, Howard Hughes, one of the key people in the Constellation's development, and owner of TWA, flew the aircraft from Burbank to Washington D.C. in less than seven hours at 346 mph (557 km/h) at 65% engine power on a publicity stunt.

The aircraft was painted in full TWA livery while still retaining its military serial number.

The other C-69 aircraft were used for different trials such as the seventh C-69 being flown to Fairbanks, Alaska for testing in Arctic conditions.

Even so, Lockheed was able to conduct tests at the expense of the government to solve problems with the aircraft's design.

The XC-69E was later sold to the Hughes Tool Company, only to be bought back by Lockheed who converted it into the prototype L-1049 Super Constellation.

That C-69 currently resides at the Pima Air and Space Museum, and is painted in full TWA livery.