 TWA started domestic 707-131 flights in March and Continental Airlines started 707-124 flights in June; airlines that had ordered only the DC-8, such as United, Delta, and Eastern, were left without jets until September and lost market share on transcontinental flights.Qantas was the first non-US airline to use the 707s, starting in 1959.The 707 quickly became the most popular jetliner of its time.