Are Ryan Air subject to the same rules about freedom of information as UK based organisations?
It doesn't matter either way. They are not a public authority, nor are they a company wholly owned by a public authority.
FOIA 2000
The Freedom of Information Act also applies to companies that are wholly owned by public authorities. These are companies that are either:
•wholly owned by the Crown;
•wholly owned by a single public authority; or
•wholly owned subsidiaries of publicly-owned companies.