Aviation Contractors - Legal Action due Breach of Contract
I had a very similar situation with another Contractor, and was advised to pursue them through an Employment Tribunal. This will minimize your legal costs as you can represent yourself.
The contract did specify that it was 'subject to the laws of England and Wales', so that may also be a factor in what you can do.
For the record it was settled out of court after about 12 months, so be prepared for a long haul.
Good luck.
Burnden