Boeing displays manned F/A-XX concept jet By Stephen Trimble Boeing Phantom Works has released a new concept image for a "sixth-generation" fighter to replace the F/A-18E/F fleet after 2025. The two-seat, twin-engined tailless concept jet is being offered for F/A-XX, a notional US Navy strategy that has not yet become a formal requirement. Although the image shows a tandem cockpit, Boeing says the aircraft could be manned or unmanned "depending on the missions assigned and technology maturity". Boeing's latest concept image for F/A-XX The new image features a blended wing and a conventional fighter shape from the cockpit area to the nose. An older Boeing concept drawing for F/A-XX released in June 2008 featured a tailless flying-wing design. The USN revealed last year that it is considering both manned and unmanned aircraft for F/A-XX, with subsonic cruising speed and up to 50h endurance.