Re: Sueing a flight school in America
If things are bad at this school, have you thought about making a formal complaint to the accrediting authority, which I assume is the CAA? Send them an e-mail asking for the contact details of the head of the accreditation section, then make your complaint with as much detail back-up as possible. While there is no guarantee you will receive an adequate or impartial hearing, it just might cause someone to look at the school a little more closely.
Regarding the courts, bear in mind that any initial action even if successful may be subject to an appeal process, which could drag things out quite a bit, and raise the money and emotional/distraction costs even higher. You may need to discuss this with your lawyer.