Shaped similar to a horse saddle, passengers sit at an angle, with their weight taken on by their legs. It allows seats to be overlapped.
The seats would also offer storage space including a shelf for carry-on bags and hooks to hang a jacket or a handbag.
The makers say the seat would allow budget airlines, such as Ryanair, to cram more passengers into their tight cabins.
The seat, designed by Italian design firm Aviointeriors Group, based in Latina, in the country's south-west, is to be unveiled this week at the Aircraft Interiors Expo Americas conference in Long Beach, California.