WASHINGTON - In the nation's skies, passengers are stretching the boundaries of decorum.
Over the weekend, United Airlines Flight 1462 was traveling from Newark to Denver when a 47-year-old man attached a small device called a Knee Defender to the seat of a 48-year-old woman in front of him.
When placed on the arms of a tray table, the Knee Defender prevents a seat from reclining. The woman who couldn't put her seat down became so upset it led to an argument, which caused the plane to be diverted to Chicago where both passengers were ordered off.
The Knee Defender's creator Ira Goldman, who is six feet, three inches tall, defended his invention.
"People want to do something to protect themselves," Goldman told CBS News. "This has always been a problem, and it's become a bigger problem the closer the seats are together."
The size of the average seat is down from the 32- to 33-inch range to just 31 inches. Some airlines have phased out reclining seats altogether.
"At the end of the day it's about revenue, and the airlines' profitability," Jami Counter with Trip Advisor Flights said.
With space at a premium, air travel has become a more intimate experience, sometimes revealing more than we needed to see. There's even a Facebook page for shaming offending passengers.
Some travelers are trying to protect their turf. At least that's why Goldman believes his small plastic Knee Defender is really taking off.
"Nobody wants to buy this product, nobody wants to carry it around with them and deploy it for giggles," Goldman said. "They do it because they've encountered problems, and they want to resolve it as best they can."
The Federal Aviation Administration says it "discourages the use of any device that alters the performance of any part of an airplane."
But passengers seeking more privacy are still searching for an edge, no matter how it looks to fellow travelers.