If you are looking at big / civil aeroplane testing, there is only one option - NTPS. <a href="http://www.ntps.com/" target="_blank">http://www.ntps.com/</a>
The costs are frightening, and the earning power frankly rather below that of an airline line captain or contracting stressman, we work in this business because we love it, not for the money, danger, glamour and various other things that are noticeable absent from the test flying coalface. The best way in is to be working for somebody who needs a TP or FTE and agree to stay put for long enough that they can get their moneysworth out of you.
G