Passengers on Europe's biggest airline may soon need to cross their legs - or queue to use one toilet shared by more than 200 people.
Ryanair has dropped its plan to charge passengers for using on-board toilets, but is pressing ahead with proposals to remove two of the three lavatories on each plane and replace them with seats.
The airline's chief executive, Michael O'Leary, told The Independent "it would fundamentally lower air fares by about five per cent for all passengers" - cutting £2 (NZ$4) from a typical £40 ticket.
The airline, which will carry 75 million passengers this year, has only one aircraft type: the Boeing 737-800.
Ryanair has installed 189 seats on each plane, the maximum allowed under current rules.
"We're trying to push Boeing to re-certify the aircraft for six more seats, particularly for short-haul flights", Mr O'Leary said.
"We very rarely use all three toilets."
A spokesman at Boeing HQ in Seattle said: "We're always listening to what our customers need but don't discuss those conversations or any business decisions."
There is no legal stipulation for an airline to provide toilets on its aircraft.