747 plane landed, Miami airport, Florida © Juan Silva, Photographer

Airlines' push to lure high-paying fliers with flatbed business seats and premium economy loungers is leaving economy-class passengers with less space.

A push over the past decade by carriers to expand higher-fare sections has shrunk the area devoted to coach on many big jetliners. But airlines don't want to drop passengers. So first airlines slimmed seats to add more rows.

Now, big carriers including AMR's (AAMRQ) American Airlines, Air Canada (AIDEF), Air France-KLM (AFRAF) and Dubai's Emirates Airline are cutting shoulder space by wedging an extra seat into each coach row. That shift is bringing the short-haul standard to long-haul flying.

For almost 20 years, the standard setup in the back of a Boeing (BA) 777 was nine seats per row. But last year, nearly 70 percent of its biggest version of the plane were delivered with 10-abreast seating, up from just 15 percent in 2010.

Of the airlines that have bought Boeing's new 787 Dreamliner—a model touted as improving passenger comfort—90 percent have selected nine-abreast seating in coach over roomy eight-abreast. And 10 airlines around the world now fly narrower Airbus A330 jetliners with nine 16.7-inch seats in each row—among the tightest flying—rather than the eight it was designed for, according to the unit of European Aeronautic Defence & Space (EADSY).

The new trend in economy seating reverses a half century of seat growth in economy class. Early jet planes like Boeing's 707 had 17-inch seats, a dimension based on the width of a U.S. Air Force pilot's hips, says Airbus marketing chief Chris Emerson.

That standard for long-haul flying increased to 18-inches in the 1970s and 1980s with the 747 jumbo and the first Airbus jets. It widened to 18.5 inches with the Boeing 777 in the 1990s and A380 superjumbo in the 2000s. Now, cost-conscious airlines are moving to lighter 17-inch-wide seats on their Boeing 777 and 787 Dreamliners and 18-inch seats for A350s.

Source: Boeing, aircraft seats; the companies, other seats; Graphic produced by Carlos Tovar, The Wall Street Journal

This doesn't sit well with many travelers, particularly those who are large or overweight. Arm rests and aisles are also getting slimmed to wedge in the extra seat, meaning more elbows get bumped. And while seats are now being designed more ergonomically, with better cushions and head rests, the improvements don't stop people from rubbing shoulders.

"I felt that I was kind of stuck in the seat" of an Emirates 777, said Ben Goodwin, a marketing manager at Birmingham University in England, who recently flew to China through Dubai. On his connecting flight, an Emirates Airbus A380, the seats were one inch wider. "I felt like I'd been upgraded, even though I was still in economy," he said.

The squeeze can help cash-squeezed airlines. Air France recently expanded the premium sections on its 777s while cutting the floor space in economy class. Yet the carrier kept the number of economy seats constant by switching from nine- to 10-abreast in the back, a spokesman said.

"On a 777, ten-abreast is the way to go," said Emirates President Tim Clark. "You'd be nuts to do it any other way."

Pressure in economy cabins also lets airlines upsell coach passengers. Air New Zealand Ltd. flies 10-abreast 777s on which fliers can book three economy seats that convert into a couch by raising the arm and leg rests.

Passengers aren't happy facing decreased shoulder room, more frequent bumps from service carts in narrower aisles and less overall comfort, said Andrew Wong, regional director of travel website TripAdvisor LLC in Singapore. Based on feedback to the company's SeatGuru website, he said, fliers "are becoming aware of increased seating abreast—particularly for the 777."

Plane makers deflect criticism, noting that seat width is up to airlines. Boeing designs its jets for airlines to do "whatever they want to do inside the cabin," said Mike Bair, Boeing senior vice president of marketing. Boeing designers focus on "creature comfort that can't be violated by the airlines," like bigger windows, larger overhead bins and mood lighting on every jet, he said.

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Airlines and airplane makers are aware that passenger hips and waist lines aren't shrinking along with the seats dimensions.

"We are mindful that we serve a wide range of customer types and our aircraft need to be configured accordingly," said senior vice president of marketing and loyalty for United-Continental Holdings Inc., Tom O'Toole, who says the airline brings in real people of all shapes and sizes to help test and select its seats.

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