I'm not totally sure what RYR is but guessing it's Ryanair as per Platimun's post - that could be a very different matter. In the UK, HMR&C (in Ireland, the Revenue Commissioners) have 6 factors which determine whether one is freelance or self-employed. These are the factors:
1. Do you have more than one client?
2. Can you choose your own working hours and days?
3. Do you use your own tools and equipment?
4. Can you be told how to do your job?
5. Are you accepting the business risk for failure?
6. Can you send someone else in your place?
Now, a freelance instructor, working for a number of schools, could well answer "yes" to those queries. I'm not sure how someone working for Ryanair could. If they do take on self-employed status pilots, then I hope there is at least and extra-statutory concession in place which exempts them from these six rules. If not, in the UK, the employer could also be "done" (and done big time as they are the ones avoiding paying Employer's National Insurance and pension contributions).
However, if it is agreed (and I'm sceptical as to the legality), I don't see why not.
Cheers
Whirls