While luxury airlines unveil multi-room apartments in the sky, the future of economy seating for the rest of us is looking smaller and even less comfortable.

In a recent patent filing, plane manufacturer Airbus included diagrams for new standing seats.

Without the context of the filing, you could be forgiven for not recognizing the diagram as airline seating.

A diagram from an Airbus patent filing showing a standing airplane seat. Image: Airbus

The design is meant to fit even more passengers on flights, specifically on short-haul trips where the added discomfort could be more tolerable, at least in Airbus' estimation.

"If you squint, the thing looks more like a medieval torture device than lounging equipment," Brian Fung wrote about the design in the Washington Post.

Airbus spokeswoman Mary Anne Greczyn said the patent diagrams are only a concept, and will not necessarily be used.

“Many, if not most, of these concepts will never be developed, but in case the future of commercial aviation makes one of our patents relevant, our work is protected,” said Greczyn.

Even though the Airbus plan is still just a concept, there is no question air carriers want to fit more economy passengers on each plane.

Boeing is working on adding capacity to its 737 narrow-body airplane model, which is used for short-haul flights. The manufacturer plans to squeeze in more passengers by reducing the space between seats by two inches.

“When you’re in the low-cost, low-fare business, you’re always striving for that competitive advantage,” Boeing's chief aircraft salesman John Wojick said.

In the next 20 years, Boeing expects air travel to double. Increasing the number of seats along with the number of planes makes sense, even if some (a lot of?) comfort is lost.

Even scholars are trying to figure out how to put more people on planes.

An academic study in the August 2014 issue of IACSIT International Journal of Engineering and Technology found that standing seats could add 21% capacity to flights, and potentially lower airfares by 44%.

"Theoretically, by having more passengers onboard the aircraft, flight ticket price can be lowered since the imposed operational costs can be shared by more passengers per flight," the study states. "To achieve this, an idea of standing passenger cabin whereby the passengers are transported in the aircraft cabin in their upright position has been proposed to reduce the operational flight costs and hence the charging ticket price to the passengers."

The study's author Fairuz Romli was looking for ways to reduce the cost of airline travel; his concept includes seats that are completely upright, something even more extreme than the Airbus concept.

Contrast these examples with Etihad's three-room suites, which include a closed-off living room, leather seating, a chilled minibar, a 32-inch flat-screen television and a personal butler, and the future begins to look bleak for the former middle class of airline travel.

Etihad unveiled its new three-room suites for the airline's Airbus A380 jets on May 4, 2014. Image: Kamran Jebreili/Associated Press

For passengers with the means to pay a premium, airlines are competing to offer the most desirable amenities. But for everyone else, the airlines' primary concern is how to serve more, not better.