I'm just struggling to see the point of the insistence that passengers must supply their passport number to Ryanair...
For Spain it is a requirement for API (Advance Passenger Information), the rest I guess it is to stop people swapping tickets without paying for the name change eg a father and son John Smith Sr and Jr have a flat in Majorca, Jr is going but something comes up and can't go and says to dad do you want my ticket after he has already checked in. Mr Smith can't take it without paying the name change fee if his passport number is different and his son has already checked in. This is the reason they require passport ID for internal flights as well, to stop people buying tickets for a penny then selling them on.