Ryanair chief Michael O'Leary today insisted he was serious about charging passengers to use onboard toilets and has instructed aircraft manufacturers to examine a credit card system rather than a coin slot.
The no-frills carrier boss said there were technical and safety issues preventing a £1 coin-operated mechanism but alternative payment options are now being explored.
The controversial pound-to-spend-a-penny plan would help raise £15 million a year for the airline, which could be passed on to passengers in fare savings, he argued.
"We have looked into this before and the problem is Boeing can't come up with a mechanism on the toilet door to take coins," he said.
"We're suggesting they go back and look at a mechanism where you'd swipe the credit card for a quid on the toilet door. They've gone off to look at that."
The proposal to charge for toilets caused a storm last week among consumer champions and industry analysts while Ryanair public relations executives even tried to play down the suggestion.
But Mr O'Leary, during one of his regular press briefings attacking the Irish Government in Dublin today, said he was confident the charge will be introduced as soon as it is technically viable.
"(People say) you can't be serious. We are serious," he said.
"If you look at it sensibly, it would reduce an awful lot of the unnecessary visits to the toilet that p*** so many passengers off onboard a plane.
"Our average journey time is one hour. Most people would go to the loo before they get on the plane, or they hold it until they land. You would only have to deal with the people who absolutely have to go.
"Frankly, if we think 20% of our passengers in a year would use the facility, if they paid a pound per passenger, it would raise about 15 million quid and would help us to pass on £15 million worth of fare savings to the travelling public."
The outspoken Ryanair chief faced down criticism over the plans which he described as another "cutting edge" initiative by the low-cost carrier, like charging for drinks.
"All this pious stuff about if you're serving teas and snacks, you can't charge for entering the toilet. All right then, we'll charge you to exit the toilets and we'll let you enter free, but you'll have to pay a pound to get back out again," he said.
"I think eventually it's going to happen. It's just we can't do it at the moment because we don't have a mechanism for charging you."