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 Austin, Texas. By the late 1980s, 172 Boeing 707s had been equipped with the Quiet 707 package. Boeing acknowledged that more 707s were in service than before the hush kit was available. Most remaining 707s are in freighter form, or as business jets. Although certified as Series 100s, 200s, 300s, etc., the different 707 variants are more commonly known as Series 120s, 220s, 320s, and so on, where the "20" part of the designation is Boeing's "customer number" for its development aircraft. The 707-020 was the original designation for what ultimately became the Boeing 720. Launch customer United Air Lines