Boeing 377 in 1950 and the first order for the 707 in 1955, Boeing was shut out of the commercial aircraft market. In the mid-1950s technology had advanced significantly, which gave Boeing the opportunity to develop and manufacture new products. One of the first was the guided short-range missile used to intercept enemy aircraft. By that time the Cold War had become a fact of life, and Boeing used its short-range missile technology to develop and build an intercontinental missile. In 1958, Boeing began delivery of its 707, the United States' first commercial jet airliner, in response to the British De
Boeing 707 already seen on the −320C. These reduced takeoff and landing speeds and altered the lift distribution of the wing, allowing the ventral fin found on earlier 707s to be deleted. From 1965, -320Bs had the uprated −320C undercarriage allowing the same MTOW. These were often identified as 707-320BA-H. The 707-320C has a convertible passenger–freight configuration, which became the most widely produced variant of the 707. The 707-320C added a strengthened floor and a new cargo door to the −320B model. The wing was fitted with three-section leading-edge flaps which allowed the deletion of the underfin. Three hundred and thirty-five of