I have seen this procedure many times while over in India. Internal flights often there see the passengers walk out to the tarmac beside the plane, point out their bags to an army of inspectors who open them, search them, and then either load them onto a baggage cart that takes them to the plane, or, if the plane is right there, load them directly on the plane.

This is a seething, hot, sweaty mass of barely-controlled chaos involving tens of security and baggage handlers, so I cannot see how Ryanair is going to perform this inexpensively in Europe.