I have no idea about Ryanair, but if you happen to be a contractor then social contribution isn't due, it is applicable only to "real" employments
Not sure what you mean here, Ryanair contractors are employed by their own limited liability companies.
If employed directly by ryanair the airline has to pay the employer part of it, if employed through another company that other company has to pay that part.
So Denti has got it quite right.