1963	The United States Air Force begins with studies for a jet-powered transport aircraft as a replacement for the C-133 Cargomaster. The aircraft was required to carry a payload of 125,000 pounds (56,700kg) over a distance of 8,000 miles (12,875km), or twice that load over a shorter distance. CX-HLS (Cargo Experimental-Heavy Logistics System) is the name of the project.
June 1964	Boeing, Douglas and Lockheed are awarded study contracts for the CX-HLS – project by the United States Air Force..
October 1st 1965	Lockheed wins the contract for the military transport aircraft CX-HLS, which should later become the C-5 Galaxy. Boeing and Douglas want to get out the financial efforts of the project by using the knowledge won during the CX-HLS studies for new commercial aircraft projects. The widebody-era begins.
February 1966	Douglas decides to delay the DC-10 program and focus on even larger variants of the DC-8. The projected 500-seaters are said not to be ready before 1975.
March 1966	American Airlines shows interest in a widebody aircraft smaller than the large Boeing project. They called it Jumbo Twin. First, Lockheed was approached, then Douglas.
April 1966	Pan American World Airways orders 25 Boeing 747s, Douglas focuses again on the widebody design.