Try talking to the Press Relations Officer at each station. If they can use it to keep the RAF in a positive light they may be able to influence the fee decision. It used to amaze me who used to get pax trips because they had good media connections (ex-footballers, tv presenters, navigators...). YOu may have to put up with the local media taking a piccie or two.
Good luck with the event, hope the weather holds for you.
GM