No, you can't move into that empty extra legroom seat on your flight. They cost extra

Dawn Gilbertson, USA TODAY

Krunal Patel didn't mind his window seat on a United Airlines flight from Chicago to Rochester, New York, in early September, but he spied a better one.

Rows of them. 

So he asked a flight attendant if he could move out of crowded row 22 into a row with empty seats. 

The response: It'll cost you. The seats were Economy Plus seats, extra legroom seats United peddles to passengers for a fee during or after ticket booking.

Patel, 32, an addiction specialist nurse, turned to Twitter from his seat to criticize the policy. United issued its stock response on the topic: Letting passengers move to those seats, it said, is ''not fair to the customers who did pay for the upgrade.''

Patel pressed the issue, arguing that there's no harm in letting passengers move to empty seats after the doors closed so they can have a better flight experience.

United fired back with an analogy that went viral.

"The customers who choose to pay for economy plus are then afforded that extra space. If you were to purchase a Toyota, you would not be able to drive off with a Lexus, because it was empty.''

Patel said in an interview that he didn't know they were Economy Plus seats when he asked to move. But he maintains passengers should be able to move into them once the plane is in the air and says flight attendants on some flights have allowed him to when he asked. Unlike first class seats, where passengers get free food, drink and other perks, the main feature of Economy Plus is extra legroom. (American and Delta, in contrast, offer free drinks as a perk in their extra legroom seats.)

"It's literally just legroom,'' he said. "The company doesn't lose money by letting passengers move up. They can only win in customer satisfaction.''

A United Airlines Airbus A319 at Dallas/Fort Worth International Airport in April 2019.

Wherever you fall on the debate – Patel was slammed as a whiny cheapskate and worse on Twitter and deactivated his account for a week – the stream of questions airlines field about their cushier economy seats underscores passenger confusion when it comes to seat options.

Unlike first class or business class cabins, which are unmistakable as you board the plane and often curtained off in flight, it's easy to overlook the section of premium seats that extend from the start of the economy cabin through the exit row seats on United, American and Delta when boarding.

Yes, they have extra legroom, but there's no partition that screams this is a special seating section, at least on domestic flights. 

Airlines carved up the economy cabin for two reasons: to create a perk for frequent flyers, who are upgraded to the more plush economy seats for free when available, and to cash in on travelers who want something comfier than a standard economy seat.

Unlike so-called preferred seats – ordinary aisle, middle and window seats scattered throughout the plane, which airlines also charge to reserve because they are in what the airline considers a favorable location on the plane –  these seats come with extra legroom and other perks. 

Want to reserve a seat on your flight? More and more, it will cost you

Here's what first-timers need to know about extra legroom economy seats on American, United and Delta

American calls its extra legroom seats Main Cabin Extra; United, Economy Plus; and Delta, Comfort+.

On some international flights and select longer U.S. flights, the airlines also offer a pricier, more exclusive extra legroom option, a step up from the main cabin but down from first class and business class. American calls it Premium Economy; United, Premium Plus; and Delta, Premium Select.

Sample prices are for seats on a round trip flight Nov. 1-3 for domestic flights and Nov. 1-8 for international/long-haul flights. Prices vary based on route, date, time, competition and time of purchase. Some airlines sell the seats as an upgrade when picking a seat, others as a type of ticket.

American Airlines

Main Cabin Extra

Online pitch: "A little bit more of everything"

Perks: Extra legroom (up to six inches); complimentary beer, wine and spirits;priority boarding (group 5). 

Where you'll find it: On every plane. 

Extra cost: Main Cabin Extra is sold as a seat upgrade. 

  • Philadelphia-Orlando, Florida: $67. (Compared with $29-$35 for a preferred seat.)
  • Orlando-Philadelphia: $61-$64 (Compared with $35 for a preferred seat.)
American Airlines offers extra legroom seats in economy for a fee. The price on a Philadelphia to Orlando flight in early November: $67.

Premium Economy:

Online pitch: "An elevated travel experience.''

Perks: More legroom, wider seats, foot rest; priority check-in, security and boarding; two free checked bags for international flights and one free bag on Alaska and Hawaii flights; free premium meal and drinks; amenity kit; blanket and pillow.

Where you'll find it: Available on 124 widebody jets on international routes, with plans for more on new planes.

Extra cost: Passengers must buy a premium economy ticket to nab a seat in that section of the plane.

  • Dallas Fort Worth-Paris: $1,759 round trip versus $1,359 in regular economy (main cabin).

Delta Air Lines 

Comfort+ 

Online pitch: "It's simple, plus means more.''

Perks: Up to three extra inches of legroom; early boarding; dedicated overhead bin space; free drinks; pillow, blanket and headset. 

Where you'll find it: All Delta mainline jets except its Airbus A350s. CDelta Premium Select is currently available on certain widebody aircraft (A350s and modified 777s) but our goal is to have every widebody in our fleet to be fitted with DPS by 2021.

Extra cost: Comfort+ is sold as a type of ticket and as a seat upgrade after booking.

  • Atlanta-New York LaGuardia: $475 round trip versus $327 round trip for regular economy. 
  • Los Angeles-Maui: $730 round trip versus $502 in economy.

Premium Select

Online pitch: "A superior cabin on select international flights.''

Perks: Up to 8 inches more legroom, meals and drinks, early boarding, two free checked bags and more.

Where you'll find it: Select widebody jets including the A350, with plans to have it on all widebody jets by 2021.

Extra cost: Passengers buy a premium select ticket or can upgrade after ticket purchase.

  • Seattle-Shanghai, China: $3,000 round trip versus $582 for Comfort + and $504 for main cabin. 

United 

Economy Plus

Online pitch: "A little extra legroom goes a long way.''

Perks: Up to six inches of extra legroom, in-seat power 

Where you'll find it: All United flights and most United Express flights.

Extra cost: Economy Plus is sold as a seat upgrade.

  • Chicago-Los Angeles: $112-$143 depending on the seat location. 
  • Los Angeles-Chicago $129-$159 depending on the seat location.
Reserving one of United's Economy Plus seats, seats near the front of the plane with extra leg room, start at $112 one way on a Chicago to Los Angeles flight in November.

Premium Plus

Online pitch: "Where comfort meets convenience.''

Perks: Extra legroom and recline; meals, complimentary beer, wine and liquor; two free checked bags; an amenity kit; Saks Fifth Avenue blanket and pillow; noise-reducing headphones; power outlets and more. 

Where you'll find it: More than 20 wide-body jets flying international routes.

Extra cost: Premium Plus is bought as a type of ticket.

  • San Francisco-London: $2,400 round trip versus $698 in regular economy.

5 things to know about airline extra legroom seats and sections

1. Upgrades to the roomier seats are not available for basic economy passengers on United and Delta. American allows travelers holding one of the no-frills tickets to buy a Main Cabin extra seat when and if seats open for sale a week before the flight.

2. It pays to do seat selection fee math when booking a ticket. With fees to reserve an ordinary economy seat on the rise, it might be worth paying a little more to get extra legroom and, on American and Delta, free alcoholic beverages.

3. You can often use miles to upgrade to better seats, even last minute. 

4. On United, you can upgrade your seat once you're on board, for a price of course. Delta lets you upgrade as late as three hours before your flight. American allows it as late as the airport.

5. You might luck into one of the seats if you didn't pick a seat when you booked your ticket and that's all that's left for an airline to assign, or if you had flight troubles and were upgraded as a token of apology.

This article originally appeared on USA TODAY: Plane seats: What American, Delta, United have in better economy seats