LONDON - Irish no-frills carrier Ryanair on Monday said it was in talks with US planemaker Boeing about adapting its aircraft so that some passengers could be placed in "vertical seating".

The low-cost carrier, which in recent months has suggested heavy passengers pay a 'fat tax' and travellers pay to use its on-board toilets, said it wants to get more people onto its aircraft by ripping out traditional seating.

Ryanair is in discussions with Boeing 'in relation to adapt the aircraft to allow people to travel in vertical seating,' Ryanair spokesman Stephen McNamara told AFP.

Passengers 'wouldn't be fully standing, they would have something like a stool to lean on or to sit on,' he added. McNamara said Ryanair was looking into removing four rows, or 12 seats, of traditional seating on its planes to accommodate the standing room.

Chinese carrier Spring Airlines was in discussions with European planemaker Airbus about a similar plan, he noted.