Every cloud has a silver lining — including the one that could lead to more comfortable seats in coach.

Passenger advocacy group Flyers Rights recently won a victory over the Federal Aviation Administration in court, with three D.C. Circuit judges ordering the FAA to look into excessively small seats on commercial flights. Flyers Rights says that flying economy could jeopardize your health and safety in the event of an emergency and potentially cause passengers to develop blood clots—a side effect of aviation informally known as "economy class syndrome."

D.C. Circuit judge Patricia Millett described her court’s ruling as "the Case of the Incredible Shrinking Airline Seat."

"As many have no doubt noticed, aircraft seats and the spacing between them have been getting smaller and smaller, while American passengers have been growing in size," Millett wrote in the court's opinion.

She’s right: Plane seats are shrinking. "The petition [from Flyers Rights] noted that economy class 'seat pitch'—the distance between a point on one seat and the same point on the seat directly in front of it—has decreased from an average of 35 inches to 31 inches, and in some airplanes has fallen as low as 28 inches. Evidence in the petition further indicated that the average seat width has narrowed from approximately 18.5 inches in the early-2000s to 17 inches in the early- to mid-2010s."

Flyers Rights may be onto something — in addition to causing discomfort, small seats really can impact your health and safety negatively.

The first issue they present is deep-vein thrombosis — the formation of blood clots. “We see patients who come home from long trips sitting still for prolonged periods of time, and not having the opportunity to move around, ending up with blood clots in their legs,” says Dr. Jonathan Schor, Program Director of the Vascular Surgery Fellowship at Staten Island University Hospital in New York. “Unless a patient is treated reasonably promptly with blood thinners afterwards, they can have bad problems with leg swelling, or pieces of the blood clot breaking off and going up to the lung,” Schor adds, estimating that his hospital treats about 50 patients a year for flight-related clots. If left unattended, they can, in rare cases, be fatal.

“The size of the seat certainly affects the ability of someone to stretch out their legs and be able to prevent a blood clot,” Schor also tells Moneyish. “We recommend to usually walk hourly — to get up and go for at least a little walk to the bathroom — to decrease the risk of blood clots.” If you can’t do that, try to stretch your calf muscles in your seat. Passengers flying for six hours or more should be particularly aware of doing these exercises, he advises.

Uncomfortable in-flight accommodations can exacerbate pain for passengers with other complications, like arthritis and orthopedic injuries, too, sending them to the doctor or hospital for treatment.

Equally as concerning, cramming people like sardines into a plane can pose risks during an emergency. "The FAA has not conducted, or alternatively has not released, any tests, whether computer simulations or rehearsed evacuations, that demonstrate that planes with modern seat sizes and modern passenger sizes would pass emergency evacuation criteria," Flyers Rights published on its website.

The FAA has told Moneyish that Flyers Rights’ statement is incorrect, saying this: “The FAA does consider seat pitch in testing and assessing the safe evacuation of commercial, passenger aircraft. We are studying the ruling carefully and any potential actions we may take to address the Court’s findings.”

This is not the first time critics have expressed concerns about moving around in cramped rows in coach. Last year, Congressman Steve Cohen (D-TN) spoke out, saying: "We have been squeezed long enough... There will be a crash, and there will be people who will not be able to get out of an airplane," according to the Washington Post.

But we may not see the end of cramped planes anytime soon, as stuffing passengers onto a plane is in airlines’ best interests. In 2015, Marketwatch wrote: “[The] more people you can get on a plane, the more money you can make.” What’s more, reducing the number of seats on a plane, while comfier, could lead to price hikes for passengers.