Hey Guys, I have never herd anything about specialized training, I'm willing to bet I clean more airplane interiors than just about anybody in this business.
I clean around 90% of all the corporate planes based out of Salt Lake. Also many Gulfstreams that are sent to me from other parts of the country. This is very much my specialty, I'm sure I do around a hundred or so a year. As Mikey alluded to , the biggest concern is going to be physical damage inside the plane, one scratch or tear could cost you thousands.
My advise to you would be, if you feel like you have the proper skills on fine fabrics and wool carpet you'll be fine. keep the moisture to a minimum, and use blowers to speed dry.
Also make sure you have the proper insurance for this. If you don't consider yourself to be a fine fabric specialist I suggest you pass on this part of the market until you get more training.