I could call the guy you were supposed to get the plane from a low-life but we are hearing one side of a story. why not PM him and tell him about this thread and invite him to put his side of the story forward. that way this could be discussed and the guy could not try to say you are harassing him. if he has nothing to hide then he will put his point across.
your lucky it was only $120 i know that is a lot of money to lose but it could have been one of the planes that are being sold for $3000+. have you informed the police? if you have paid for something then you should get the goods you paid for otherwise it is theft.
good luck i hope you either get your plane or your money back