Supersonic jet startup Boom’s future is in doubt after every major jet-engine maker refuses to help Engine manufacturers are not interested in helping Boom build a supersonic powerplant, per FlightGlobal. The comments come after Rolls-Royce announced an end to its contract with Boom in early September. Travel analyst Henry Harteveldt told Insider that Boom may build its own engine, which could be advantageous. Boom Supersonic may be forced to make its own engine for its ultra-fast Overture jet. In 2020, engine manufacturer Rolls-Royce signed an "engagement agreement" with Boom to explore an engine that could power the faster-than-sound Overture , which already has orders from United and American Airlines . However, Rolls-Royce told AIN Online in early September that it has since left the table. "We''ve completed our contract with Boom and delivered various engineering studies for their Overture supersonic program," Rolls-Royce said. "After careful consideration, Rolls-Royce has determined that the commercial aviation supersonic market is not currently a priority for us and, therefore, will not pursue further work on the program at this time," the company continued. "It has been a pleasure to work with the Boom team and we wish them every success in the future." After Rolls-Royce''s comments, GE Aviation, Honeywell, and Safran Aircraft Engines have all told FlightGlobal that they are not currently interested in making a supersonic engine for Boom.