The problem is there is a over supply of aircraft fitters, i can recruit as many as i wish, (however the same cannot be said of vehicle mechs who are in shorter supply) ,the reason for this i feel is that the industry is swamped with unqualified people who have never undertaken a aircraft apprenticeship passing themselves off as "aircraft fitters" the majority of these people originated from places such as the big old BAE factories who were recruited in droves in the good times as semi skilled staff on producton work and then after a couple years left and went on the contracting circuit as "aircraft fitters"
The only way the rates will ever rise is when fitters are required to legally hold some form of qualification before they can be employed on aircraft work, its just far to easy for someone handy with tools to become a "aircraft fitter" im afraid, bottom line, if you wish to earn a good salary get licensed, and obtain some decent type rating on that licence