There is nothing special about aisle seat 18D on Delta Air Lines Flight 2876 from Atlanta to New York.

No extra legroom, free drinks or priority boarding.

But try to reserve it for a January weekend getaway and a price tag pops up: $59.99. One way. On top of the ticket price.

Seat 18D is an ordinary aisle seat on American Airlines, too, but it'll cost you $39 one way to reserve it on a flight between Dallas and Boston in mid-February. Prefer 12D a few rows up? That'll be $43. 12E,  a lowly middle seat, is going for $36.

Seat selection fees, once the province of no frills discount airlines like Spirit and Allegiant, have become big business for major airlines – and a source of frustration and confusion for travelers.

They are prevalent and pricey at American and Delta, and United starting selling them on Dec. 14, a move the company announced in August. United appears to be starting slow, with limited seats per flight and an initial fee of $9 each way, according to a spot check of routes by USA TODAY.

The seat assignments for sale are "preferred'' seats, so named because they are in areas of the plane airlines say passengers prefer, such as aisle and window seats closer to the front.

United President Scott Kirby, a pioneer of seat fees when he was president of US Airways a decade ago, has long said paying different prices for seats on a plane, even if the only perk is getting off sooner than other passengers, is no different than paying higher prices for seats closer to the front at a concert or sporting event.

Brett Snyder, a former airline employee who writes the Cranky Flier blog and runs a travel service called Cranky Concierge, calls that a "completely ridiculous comparison.''

"It's not like you need a view of the pilot here,'' he said.

TODAY IN THE SKY: November route roundup: Where airlines are adding service

Bob Denny calls preferred seats a ripoff. Denny, who lives in Ohio and travels overseas for his job as an anti-terrorism assistance instructor for the U.S. Department of State, says he paid about $65 for what he thought was a seat upgrade on an Atlanta-Paris flight on Delta partner Air France in September.  Like many business travelers, he paid for the "upgrade'' with his own money to stay compliant with his company's travel policy.

For that price, Denny figured he was in the extra legroom seats in the front of the economy cabin.

He wasn't. He had purchased a "preferred'' aisle seat in what he called the "sardine'' section. He tried to get a refund but has had no luck.

"I think it's a fleecing,'' he said. "There's nothing preferred about it.''

Airlines get plenty of questions and complaints about preferred seats on social media.

The government doesn't require airlines to disclose seat fee revenue as it does with bag fees and reservation change fees, and airlines don't publicly break them out. (Except for Southwest, which doesn't assign seats but took in $358 million from its version of a seat fee called EarlyBird check in.)

Veteran travel analyst Henry Harteveldt, co-founder of Atmosphere Research Group in San Francisco, estimates seat selection fees generate "well north of'' half a billion dollars a year for large airlines that charge them.

"It could be substantially higher,'' he said.

Harteveldt says he recently booked a flight on an airline on which he doesn't have elite frequent flyer status (elite members generally can book preferred seats for free.) When he pulled up the seating chart, all that was available to reserve without extra charges were center seats.

"I coughed up about $48 to have a window seat,'' he said.

TODAY IN THE SKY: First look: Delta shows off first Boeing 777 retrofitted with new cabin interior

Jay Sorensen, president of airline consulting firm IdeaWorks and an expert on airline ancillary revenue, said the the adoption of seat assignment fees in the last two years has been surprisingly rapid.

"The big three – American, Delta, United – have been going down this path of copying the playbook from the low cost carriers,'' he said.

Sorensen says airline seat fees are now a strong second to baggage fees (when you include fees to upgrade to airlines' economy seats with extra legroom and other perks. Delta calls it Comfort Plus, American, Main Cabin Extra and United Economy Plus.

Quoted:
Just recently booked four tickets to Ireland myself. They assigned seats in a manner that forced me to move just about all of the seats to even get it with two together. Random seats are blocked off to make sure you have to upgrade to a much higher level to do it. Total bullshit.

Quoted:
Without fail, every time I decide to pay a little extra for a specific seat... the second I sit my ass down some random lady starts begging me to switch seats with her scared kid so they can sit closer to each other

I usually give in out of decency... but NEVER AGAIN lol

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I don't pay to choose seats   (small) perk of being an extremely frequent flyer

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Just bought tickets on AA and when I was selecting my seats there were seats that where $30-50 more for select seats and $80 more for select seats but these included complementary booze. I did not pay extra for the seats I wanted though.

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ETA:

Also have a membership to expert flyer.  I always check seat upgrade availability for both status and mileage redemption.

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Meh when you're diamond on Delta you get a good seat. But their 6 levels of boarding is crazy and gay, but I think they just changed it.

And F United from O'hare

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These are the reasons (along with TSA) that I will drive 3 days to avoid flying for 1.

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How long is the drive to Hawaii?  

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These are the reasons (along with TSA) that I will drive 3 days to avoid flying for 1.

Quoted:

I always say no.  I picked the seat I picked because of my own reasons.  Invariably when I ask "what seat is yours," they point to a middle seat, next to a crying baby, large person, or other major annoyance.

Yeah, they didn't pay the fee....I picked early and got something I wanted.  Why should someone who didn't pick early and got saddled with a shit seat get my less shitty seat because they are begging?
The most powerful word in the english language is "no," by the way.  

Quoted:
Booked a United flight last night to the west coast and got whacked with a $18 fee cause I chose a wing seat.

Wonder what more they will be coming out with...

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What if you pay more for specific seat
then a stewardess makes you move?

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I love Southwest..... I'm in my 20th year of traveling for a living.

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I've not flown in a very long time... are we saying you have to pay extra to get seated together?... as in you buy two tickets and they just throw both persons on the plane randomly..?

Quoted:
What if you pay more for specific seat
then a stewardess makes you move?

Quoted:

How long is the drive to Hawaii?  

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Being retired with a nice motorhome beats the HELL out of flying. Service in a snap form the copilot. If we crash it's only a few feet to the ground. No TSA. Guns everywhere. Boxerdog. Creative chef level dining. Rental truck is attached to motorhome. I flew our airplanes for years and years. This is better.

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Airline pricing and fees are verging on satire.

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I've never had to ask someone to switch seats, but I would turn right around and ask the annoying fuck beside me to switch with my kid that was next to you. Then I would order a double Jack and Coke, give a cheers to you and smile the whole fucking flight.

Quoted:
Just recently booked four tickets to Ireland myself. They assigned seats in a manner that forced me to move just about all of the seats to even get it with two together. Random seats are blocked off to make sure you have to upgrade to a much higher level to do it. Total bullshit.

Quoted:
Without fail, every time I decide to pay a little extra for a specific seat... the second I sit my ass down some random lady starts begging me to switch seats with her scared kid so they can sit closer to each other

I usually give in out of decency... but NEVER AGAIN lol