On April 16, 1944, a C-69 flew from Burbank, California to Washington, D.C. in 6 hours, 57 minutes, 51 seconds. There was even bad weather along the journey.
After World War II
In 1948 an improved Constellation, the C-121 was constructed. One of them was General Eisenhower's aircraft, the "Columbine I" when he commanded NATO forces. General MacArthur had one called the "Bataan."
In 1951 the design was upgraded to the C-121C with 3,500 HP engines. One was the "Columbine III" which was President Eisenhower's aircraft.
The Lockheed Constellations were used into the 1960s by airlines.