Depends on where the aircraft is to fly. Making an assumption that it can technically be done in the next few years who gets ground controll of the aircraft? Not a big decision in say domestic USA, but a big political, security and legal problem for an aircraft flying Austrlia to UK.I'm sure the countries being overflown will want some input but security questions alone would cause some serious heartburn.In the end I suspect the status quo will remain for the foreseeable future.