The 'Ryanair effect' for major airports is next to worthless. It may increase passenger numbers in the short-term, but will not bring in worthwhile income and profit as Ryanair won't pay landing fees at a reasonable rate and cheepskates who want to travel for £10 are not going to spend much in the terminal either. If they've any sense they will show Ryanair the door like Manchester did rather than lose money and upsetting other airlines by pandering to O'Leary.