Anyone who has a basic knowledge of the industry will know that virtually every airport outside of the major hubs offers inducements to airlines to entice them to operate there - whether it be fuel, fees etc. This is hardly exclusive to Luton - the theory being is that the economic input from passenger numbers vastly outweighs the cost to the airport.
Indeed!.....Most of Ryanair's early growth in Europe at the minor airports miles from anywhere was funded in this way! When some stopped the payments RYR had a habit of terminating service!