You’re not imagining it: Airline seats are generally getting smaller.

But while many airlines have been slimming down their seats over the past few decades, we’ve been bulking up. According to the World Health Organization, the global prevalence of obesity has doubled since 1980.

“Seats are getting smaller and smaller as airlines look to squeeze revenue from their economy seats,” noted Ranga Natarajan, the senior product manager at SeatGuru, a website that rates the best and worst seats on nearly every plane in the industry.

In the 1960s, a seat width of 17 inches was standard, and for a period in the 1990s and early 2000s, that grew to 18.5 inches with the introduction of the Boeing 777 and Airbus A380.

Recently, however, airlines been filling planes to a capacity that Natarajan calls “historic proportions.”

“Airlines used to fly at 70% capacity. Now, that number is closer to 80 to 85%, which means every middle seat is occupied, so the elbow room just isn’t there,” he said.

To fit in the extra seat, passengers are now facing a width that is 17 inches and in some cases as narrow as 16 inches, a state of affairs that has pushed airplane manufacturer Airbus to launch a new marketing campaign called “it’s the seat.”

In a call to action to make 18 inches the industry standard, Airbus partnered with the London Sleep Center. They tested a small sample of six adults and found that passenger sleep quality improved 53% in the larger seats.

“If the aviation industry doesn’t take a stand right now, then we risk jeopardizing passenger comfort into 2045 and beyond,” said Kevin Keniston, Airbus’ head of passenger comfort, in the company’s press materials.

People’s growing proportions aren’t the only issue, Airbus spokeswoman Ruth Nye said.

“In the early days of jet travel, people were flying less frequently and over shorter distances. Also, due to a lower load factor, many had empty seats next to them,” she said, adding that all of Airbus’ long-haul aircraft have been designed to accommodate 18-inch seats.