Ask Clayton Conway about the worst seat on a plane, and he’ll tell you about the time he flew from Denver to Seattle on Frontier Airlines.

"It was the worst flight experience I’ve ever had," says Conway, who manages a digital marketing agency on Camano Island, Wash.

"I was seated in a bulkhead seat that not only didn’t recline but was also kitty-corner to a restroom,” Conway says. “So every restroom visitor would inadvertently waft the nose-wrecking toilet stench directly toward me. It was horrific, and there was no escape."

Which airline seat is the worst? That’s a hard question to answer with any specificity. On an American Airlines Boeing 737-800, for example, the seat-rating site SeatGuru warns of several “bad” seats, denoted in red. They include all the seats in row 30, at the back of the aircraft. The reasons are obvious: The seats in row 30 are next to lavatories and don’t fully recline.

But all the row 30 seats aren’t equally bad. The middle ones — 30B and 30E — are particularly torturous. In addition to the seats being next to the lavatories and not reclining, a passenger is confined on both sides by other passengers. That’s a trifecta.

If you’re worried about getting a bad airline seat, it pays to check multiple sources before booking. Consult SeatGuru or another site, such as SeatMaestro, or talk to a travel adviser. Here’s a short list of “don’ts”:

· Don’t buy the cheapest ticket. "Step back from the computer and the thirst to score the lowest fare," says Jeff Klee, CEO of CheapAir. Instead, he says, make a list of "must-haves" when picking a flight. Do you need an assigned seat? Do you need a window or an aisle? Extra legroom?

Make sure the flight you book has all of your must-haves. Sure, you’ll have to pay extra. "But you’ll be glad you did on your travel day," Klee says.

Years ago, when my family lived in Austria, my parents found the cheapest fares from New York to Vienna on Tarom, the Romanian flag carrier. Our seats were in the back of the aircraft, next to the lavatories, with zero recline — and in the smoking section.

· Don’t wait until the last minute to book. If you buy a cheap ticket at the last minute, you’re practically asking to end up in 30B. Exception: If you book an unrestricted economy class or business class seat, you’re in luck. Most airlines set aside a few choice seats for big spenders.

· Don’t forget to vet your carrier. Not all airlines are the same, says Tim Leffel, author of The World’s Cheapest Destinations. Some domestic airlines, such as JetBlue and Southwest, have reputations for providing more legroom. For some trips, Leffel also suggests looking at a low-cost airline such as Mexico’s Interjet that’s "known for not jamming in so many seats."

· Sometimes it’s not a matter of avoiding a particular seat, but an entire airline. Conway’s experience is a case in point. Frontier Airlines part of a group of ultra-low-cost carriers that includes Allegiant Air and Spirit Airlines — is not known for seat comfort or amenities.

· If you don’t have a seat assignment, mind your manners. "Don’t dress badly, be rude, loud or otherwise self-important," says frequent flier Matt Woodley, who writes a blog about international moves.

According to Woodley, nothing says “I belong in the middle seat” like “traveling in your jammies, being loud and obnoxious, or incessantly bugging the gate agents about how important you are, how long you’ve been waiting or how important your appointment at the other end is.”

Ticket agents can and do judge you based on your appearance or behavior. They’re only human.

It’s worth exploring why air travel somehow feels worse these days. My family’s flight on a communist-era Romanian airline was, in many respects, less degrading than air travel today. No one demanded that we pay extra to sit together. Those economy class seats, despite their undesirable location, came with a humane amount of legroom. The flight attendants served two meals and drinks at no extra cost.

Airlines use our collective fear of the worst seat to prod us into paying extra for seats that have the same amount of legroom we had on that Tarom flight. They know we’ll fork over more money to avoid the 30Bs of the world or to avoid being separated from our kids. In short, our fear of getting stuck on the worst seat on the plane is just one of the industry’s powerful tools for increasing profits.

Christopher Elliott is a consumer advocate, journalist, and co-founder of the advocacy group Travelers United. Contact him at elliott.org.