When she has the time to get to the airport early, Anne Marie Mitchell, a communications professor in Chicago, will treat herself to a few hours in the airport lounge, either using a free pass from her airline credit card or paying a day-use fee.

“You get access to a bar, a nice clean bathroom, snacks and it’s uncrowded,” she said. “It makes traveling more fun.”

Airline lounges, bastions of civilization in airport terminals that are now often overstuffed with irritated passengers, thanks to flight delays and cancellations, have long been the retreat of the frequent-flying elite, forward-class ticket holders and those with expensive credit cards.

Now, with leisure travelers leading the recovery of the airline industry as business traffic lags, some clubs have made it easier for relatively infrequent fliers to claim a few predeparture perks, while others — including Delta Sky Club, which adopted a new rule that no user may enter the club more than three hours ahead of their scheduled flight — grapple with growing pains.

The expanding world of clubs

Historically, legacy carriers, including American Airlines, Delta Air Lines and United Airlines in the United States, have operated lounges for passengers flying in first and business classes, as well as frequent fliers who qualify for membership. Their offerings sometimes include standard clubs (such as United Club at United) and more exclusive ones for forward-class fliers on long-haul international flights (United Polaris).

Another class of clubs welcomes members flying any carrier. These include Priority Pass, which offers access to more than 1,300 lounges in more than 600 cities (membership plans include 10 visits for $299 a year).

In this case, a lounge might be an actual airline club, such as the Plumeria Lounge from Hawaiian Airlines that Priority Pass members have access to in Honolulu; public airport restaurants that offer a food credit, such as Stephanie’s restaurant at Boston Logan International Airport; other club brands, such as Minute Suites, which are private rooms, at Dallas-Fort Worth International Airport; or airport amenities such as the Be Relax Spa at Los Angeles International Airport, where members get credit for a chair massage.

Increasingly, lounge users are not airline devotees, but holders of expensive credit cards.

“It’s become popular to bundle lounge access with a premium credit card,” said Gary Leff, who writes the airline blog View From The Wing. “It’s a way of selling cards and retaining members.”

American Express Platinum card holders have access to many airline lounges, as well as the company’s own Centurion Lounges, which are found in 13 American cities — with new ones coming to Hartsfield-Jackson in Atlanta and Washington’s Reagan National in 2023 — for a total of more than 1,400 lounges globally. The card costs $695 annually, with credits up to $400 a year in hotel and airline expenses, among benefits.

Now other banks are getting into the lounge game, including Capital One, which opened its first lounge — with a stationary cycling room, showers and craft cocktails — in November at Dallas-Fort Worth, with follow-ups planned for Denver and Washington Dulles outside of Washington, D.C., in 2023. Entry is restricted to owners of the bank’s Venture X card, which costs $395 a year, and their guests; the card’s perks include credits up to $300 for travel purchases.

JPMorgan Chase has announced it will open its own brand, Chase Sapphire Lounge by the Club, with six global locations, including Boston, Phoenix and New York’s LaGuardia Airport beginning next year and available to holders of its Chase Sapphire Reserve card ($550 a year with benefits, including $300 in credits on travel purchases and Priority Pass membership).

What price sanity?

In these times of airline mayhem, many travelers are willing to buy themselves out of the airport hell of sitting on the floor to get close to the only available electrical outlet in the concourse, a rescue offered by pay-per-use clubs.

Plaza Premium Group, which has restaurants, lounges and hotels in more than 70 global airports, recently introduced its PPL Pass Americas, which costs $59 for two visits within a year to most of its lounges in North, Central and South America. The pass gets you into stand-alone Plaza Premium Lounges and the airline lounges it operates for the likes of Virgin Atlantic, Avianca and Air France. There are six eligible lounges in the United States, with a new location in Orlando, Fla., expected to open later this year.

“The first and business top-tier premium frequent flier is well taken care of,” said Jonathan Song, the director of global business development for the company. “The remaining 85 percent are economy class and are airline agnostic, which is where we see the rise of affordable luxury. People want to enjoy the V.I.P. services they would in first and business, but may not want to spend that amount for the ticket.”

Now affiliated with American Express, Escape Lounges, also called Centurion Studios, has 14 locations, including Minneapolis and Sacramento, Calif., that offer pay-per-use plans at $40 a visit, if booked online 24 hours in advance, and $45 at the door (Platinum cardholders have complimentary admission). Access offers standard perks, including free internet access, food and drinks, and new locations are expected later this year at airports in Fort Lauderdale, Fla., and Columbus, Ohio.

Another option, the Club, has 16 locations in the United States, including New Orleans and Seattle, and two in London. It sells no memberships and runs strictly on a pay-per-use basis at $45 a visit (free to Priority Pass holders).

For one-stop shopping, the website and app Lounge Buddy sells airport lounge passes starting at $25. Among lounges with similar amenities at, for example, London Heathrow — such as Wi-Fi and free food and drink — the site offers $39 passes to Plaza Premium Lounges and $74 to the Lufthansa Business Lounge. In Barbados, a pass costs $27.

United offers day passes to its United Clubs for $59 on its app. Annual memberships cost $650 or 85,000 miles for most frequent flier members. American Airlines also sells one-day passes to its Admirals Clubs for $59 or 5,900 miles. Delta does not offer paid access.

Considering the high prices of airport concessions — a vendor at LaGuardia was recently censured for selling a $27 beer — hungry travelers may find admission worthwhile.

“On a one-off basis, with a long connection, you can make the math work for you, depending on how much you would otherwise spend,” Mr. Leff said. “You can eat and drink your money back, and maybe it’s less crowded and you have a power port to plug into.”

Beyond complimentary gin and tonics, fliers in a booking jam may find it valuable to pay the fee at an airline lounge to get prompt airline assistance.

“If your flight is canceled and there’s a two-hour wait to talk to someone, pay the $50 club fee and you’ll get access to agents who tend to be the most experienced and can do amazing things to get you where you need to be,” said Brian Kelly, the founder of the website the Points Guy, which covers loyalty rewards.

No room in the club

Depending on when you fly, even buying your way in may be out of the question these days as pass holders have been turned away, thanks to capacity crowds.

“Centurion lounges are like going to TGI Friday’s. You check in and they buzz you when there’s open space,” Mr. Kelly said. “As we’ve seen with travel this summer, people are raring to go and have missed out on premium experiences the last few years, so when they’re traveling, they are splurging.”

The crowding problem isn’t necessarily new, but some new factors, including airport staffing shortages, have exacerbated it.

“Many better lounges were crowded before the pandemic,” Mr. Leff said. “Now people are arriving earlier because of the uncertainty of security lines and then finding they have extra time to kill.”

“Now there are even queues outside the lounge, something I had never encountered in the pre-Covid travel era,” wrote Haris Stavridis, the owner of a public relations agency in London, in an email. “Lounges are supposed to be your safe haven, but they’re becoming problematic now.”

Some clubs are addressing the surge, including Delta Sky Clubs with its new three-hour rule. Though it is nearly doubling the size of its San Francisco Centurion Lounge and tripling its club footprint in Seattle this year, American Express will begin charging cardholders for guests (adults, $50) beginning next year unless a user spends at least $75,000 a year on the card.

Clubs may be victims of their own success, but accessing them may still be the cheapest upgrade-per-perk you can get when flying today.

“Everybody has some kind of privilege now with Amex or miles or buying in,” said Patrick Rollo of Providence, R.I., who travels frequently for his work in real estate. “So, everybody’s going to the lounge.”

Elaine Glusac writes the Frugal Traveler column. Follow her on Instagram @eglusac.