The idea, which the Associated Press said would radically alter intercontinental travel, was still in its early stages and the airline was polling customers to gauge interest, Lufthansa spokeswoman Amelie Lorenz said.

We are going to analyse the results of the survey and then we will decide whether to proceed or not. But the first results have been very positive,” she said.

Most airlines already provide flat bed seats on long-haul range for first- and business-class customers.

Economy-class passengers get nothing more than reclining seats and usually little leg room, factors blamed for causing deep-vein thrombosis.

Airlines have been reluctant to introduce fully reclining seats in economy class because they take up more room, reducing the number of passengers they can squeeze in and reducing profits.

But a computer-generated image provided by Lufthansa features a layout of berths stacked three-high in diagonal rows - herringbone-style - along the sides of the plane, and additional bunked berths in a wide central aisle.






The proposed layout appears to represent the lower deck of the world's largest commercial airliner - the twin-level Airbus A380 - but Ms Lorenz told Associated Press that the design was just one of those under consideration.

The A380 will fly on Lufthansa's ultra-long haul flights, including those from Germany to North America, Australia, South Africa, and the Far East.