The idea of paying to use the lavatory in an airplane has been the punch line of many jokes about airline fees. "What are they going to do, start charging to use the toilet?" Why, yes.

Just one day after U.S. budget carrier Spirit Airlines announced that it will begin charging passengers for the carry-on bags they bring with them, Ryanair announced it would finally make good on its idea [threat?] to charge passengers to use the loo. Ryanair plans to charge £1 or €1 for each visit. Talk about "pay as you go."

The Daily Mail reports that Ryanair is working with Boeing to redesign the cabin and develop coin-operated toilets on 168 of its planes. The airline is also looking at reducing the number of toilets on board, a move that will surely get the attention of regulators and advocates for passengers with special needs.

There you have it. What had become the butt end (yes, that's a pun) of many an airline joke is about to give Ryanair the last laugh. About the only thing left to wonder about this move is this: how likely is it that the airline will also install a toilet timer to limit an individual's privacy and perhaps increase the frequency of use? And when the time is up, the door swings wide open! Now that's something nobody wants to see.