How much extra would you pay for a little more legroom on a long flight in the cramped confines of coach?

Delta Air Lines is betting it’s $80 to $160. The Atlanta-based airline is installing what it calls an “economy comfort” section on planes that fly overseas or other long international routes, and is now selling the roomier, pricier seats for flights next month and beyond.

The main benefits of the extra fee: up to 4 inches of extra legroom, plus 50 percent more seat recline.

Delta’s gambit is the latest effort by airlines to find some middle ground between pack-’em-in financial imperatives and added comfort short of a first-class upgrade. United Airlines has long offered several coach rows with more legroom on many flights, including domestic, and will expand the concept to merger partner Continental. Other airlines have tried versions of the idea over the years.

Delta’s “economy comfort” seats will take up the first few rows of coach, and those who pay for the privilege also get to board early and have free cocktails.

It may not sound like much, but frequent fliers say 4 inches makes a difference, particularly for those who are tall or who need to work on a laptop during the flight.

“I promise you, 4 inches is a lot of room,” said Delta frequent flier Mike Stetz, who lives in Augusta. “The added space in there would be very attractive.”

Stetz, who works in sales in the manufacturing industry and travels about twice a month, said the extra space would allow a flier to work on a full-sized laptop. “When you’re on a flight that long, you need to be productive.”

Delta sells preimum coach seats at booking, with the fee based on flight length and the base fare, and on June 1 will begin selling them at check-in as well. Frequent fliers are a primary target, and those with platinum or diamond elite status can get the premium seats free if available.

But even a hint of luxury in the crowded, stuffy coach cabin has broader allure, airline industry experts say.

“There’s a certain elitist appeal to these types of services,” said Jay Sorensen, a consultant whose firm, IdeaWorks, specializes in frequent flier programs.

“It’s really an intangible thing, but there certainly are customers out there who find it delightful to get on the airplane first, to be on something that is different from everyone else.”

Delta will put special seats covers on the premium seats, but otherwise the rows won’t look much different. The seats are the same as in the rest of coach.

Alan Saul, an international insurance broker who lives in Sandy Springs, said he has flown in Delta partner KLM’s premium economy section and he plans to try Delta’s on his next overseas trip.

He said he looks forward to extra legroom and being able to “lay back a little better,” adding he’d use it for either business or vacations. “I think it’s worth it,” Saul said.

Some companies may allow employees to expense economy comfort, even if they won’t pay for full business class, according to Georgia State University professor of marketing Ken Bernhardt

That would offset the effects of the recession for some, he noted.

“In today’s economy, many business travelers have cut back on the number of executives who are eligible to fly business class over the ocean,” Bernhardt said, adding that premium economy seats allow them to make a compromise.

Delta said the sections are part of a larger $2 billion investment the airline is making to “improve the customer experience” in the air and on the ground.

One negative for airlines is the implied admission that regular old coach is barely tolerable these days.

Stetz, for instance, remembers a time when a few extra inches of legroom was part of the flying experience for all.

“There’s another way to look at this, is that Delta is giving you the 4 inches back that they took” in the past, and charging for it, he said.

Those who remain in non-premium coach can at least take comfort from this: Delta says it is not taking legroom away from the rest of coach to create the premium seats, but rather gaining the space by removing a row or so, depending on aircraft type.