 As a derivative, the 720 had low development costs, allowing profitability despite few sales.Compared to the 707-120, it has a length reduced by 9 feet (2.7 m), a modified wing and a lightened airframe for a lower maximum takeoff weight.Powered by four Pratt & Whitney JT3C turbojets, the initial 720 could cover a range with 131 passengers in two classes.