Aerion Supersonic in Reno, Nev., has been working for the last decade to develop a supersonic business jet, and now the aerospace giant Airbus has joined the team as a partner. Airbus said in September that it will provide a team of senior engineers to work with Aerion to help shepherd the design through the complex certification process. (The companies are currently working together in the initial stage of their engineering collaboration.) Robert Bass, chairman of Aerion, says that the partnership will help t…