The post World War II airliner market was rather like the competition between bomber aircraft in the war. Better engines, sleeker designs, more load carrying capability, longer range, were all sought after by the various airline companies both in the US and overseas. TWA bought the Lockheed Constellation, which could carry about 100 passengers on transatlantic flights. Pan American, the other US powerhouse airline bought "Connies", but they also had a long standing relationship with Douglas Aircraft. The Douglas DC-7 could fly New York to LA nonstop, but couldn’t do the Atlantic. The DC-7C could fly the Atlantic nonstop.
Unfortunately for the Connie and the DC-7, the Boeing 707, Douglas DC-8, Convair 880, and the VC-10 were coming into service, and the DC-7C began to disappear.