Budget airlines may launch standing-only seats in 2026 after the designs were said to have passed the necessary safety tests. The upright rollercoaster-style padded seats allow passengers to lean but not sit, creating an extra 20 percent capacity per flight.

The Skyrider standing seats were first revealed in 2018 by Italian manufacturer Aviointeriors, with the expectation being that they would only be used for flights under two hours.

A spokesperson for Aviointeriors said in 2018: "The Skyrider 2.0 is an innovative seat. It allows an ultra-high density in the aircraft cabin.

"Skyrider 2.0 opens the travelling experience to a wider passenger market, creating also a useful space for the introduction of mixed classes boarded on the same aircraft.

"Its main feature is the original bottom that ensures an increased upright passenger position allowing installation of the seat at a reduced pitch, while maintaining an adequate comfort."

The spokesperson added: "The design of this seat enables carriers to increase the passenger number by 20 per cent, allowing increasing profits for airline companies."

Ryanair CEO Michael O'Leary has backed "standing berths" since 2012 and suggested fares could be as low as £1. 

However, as it stands no airline has confirmed it will be introducing the seats.