Qantas' idea for underfloor beds for its upcoming order for an ultra-long-range aircraft to serve London and New York non-stop from Sydney and Melbourne could bring back the romance of travel for more passengers. But the concept is not new. In fact, virtually all long-haul airlines have crew beds either underfloor - or in the roof of the aircraft. See: Qantas' spectacular Quokka video In London on Tuesday, Qantas CEO Alan Joyce said at an Aviation Club lunch that on the proposed ultra-long-haul aircraft the ability to carry cargo will be limited thus there would be underfloor space that could be utilized. "If we're not carrying freight you can do something with the underfloor area where cargo is on the aircraft. Do you have an area where people can walk? Do you have berths, like on a train?" Mr Joyce said. "There's a lot of 'out there' thinking that's going on. I don't know if in 2022 if there's another going to be another class but if there is Qantas is likely to be the airline that creates it." One concept that Boeing floated last decade with its idea for overhead beds for the 747, was that they could be sold to premium economy class passengers for a fee as business and first class already have beds.

Up till now the concept for passengers has never really taken off as the space is too valuable for cargo. And passengers have never been seated in the underfloor spaces for take-off and landing as there are major structural issues surrounding the beefing up of the belly of the aircraft to protect passengers in the event of a wheels-up landing. McDonnell Douglas, now part of Boeing, found all this out in 1991 when it proposed its downstairs Panorama Deck for the MD-11 with passengers seated for the entire flight. Certification problems plus a lack of interest by airlines killed the concept.

Lockheed actually built a downstairs lounge in its Tristar for one customer Pacific Southwest airlines in the early 1970s. Five were built but PSA found the first two jets too big for its route network and returned them to Lockheed and all were sold to LTU the German charter carrier.

Boeing and McDonnell Doulas also proposed downstairs lounges on their 747s and DC-10s but no airlines took them up.

If the area is used just as a lounge after take-off then the certification issues are eliminated. However, Boeing did have a small downstairs lounge on its Stratocruiser in the 1950s. Boeing also proposed a lounge and beds in the ceiling of its Boeing 747-8I as a counter to the A380 but no airlines took up the option.

But there is no question that the new ultralong haul aircraft being proposed for the next decade will have free space and a whole new way of travel may emerge. Mr Joyce also raised the prospect of treadmills to give passengers exercise. Again this was floated by McDonnell Douglas in 1991 on its proposed MD12.