“We continue to look at ways of making our operation more efficient so we can offer even lower fares than we do now,” Tiger Airways director, Steve Burns, said.

“Everything we do is about offering the lowest possible fare then allowing our customers to choose what, if any, extras they wish to pay for.

However, Jetstar spokesman Simon Westaway said the airline would never contemplate vertical seating or charging passenger to use the bathroom.

“A lot of Jetstar destinations are over two hours and longer, so the stand up seating idea doesn’t register on our radar. We have a completely different business model to Ryanair,” he said.

“It’s an interesting concept but I can’t see how this would fly in our part of the world."

Ryanair’s chief executive Michael O'Leary said the Irish airline will fund the controversial travel option by charging customer to use the restroom during flights.

His proposed “vertical seats” would be available in a special standing-room only sections in the rear of commuter flights lasting an hour or possibly longer.

Tickets would cost between $7 and $14 per passenger, Mr OLeary said in TV interview.

The new seating proposal was welcomed by Mr Burns, who said Tiger Airways wouldn’t rule anything out.
“Selling cheap fares is easy. Doing it profitably means having to continually innovate and evolve so that the cost base continues to reduce.”

Ryanair will conduct safety testing for the new vertical seats next year.

"We've been looking at is taking out the last ten rows of seats so we will have 15 rows of seats and the equivalent of ten rows of standing area," Mr OLeary said.

However, Civil Aviation Authority officials harbor doubts that the revolutionary new seats would pass safety rules.

"It's aviation law that people have to have a seat-belt on from take-off and landing so they would have to be in a seat. I don't know how Mr O'Leary would get around that one," said a spokesman.