But "Boom Supersonic is transforming air travel with Overture, the world’s fastest airliner, optimized for speed, safety, and sustainability. Serving both civil and government markets, Overture will fly at twice the speed of today’s airliners and is designed to run on 100% sustainable aviation fuel (SAF). Overture’s order book, including purchases and options from American Airlines, United Airlines, and Japan Airlines stands at 130 aircraft. Boom is working with Northrop Grumman for government and defense applications of Overture. Suppliers and partners collaborating with Boom on the Overture program include Collins Aerospace, Eaton, Safran Landing Systems, Rolls-Royce, the United States Air Force, American Express, Climeworks, and AWS."
This^ is significant support they already have. So they could operate for 10+ years, which seems like they will (even if they are just in R&D and burning cash). In a way, it is viable to the employees and suppliers, if they get paid for such a long time haha.