Spirit Airlines on Sunday began charging passengers to carry luggage on flights, an industry first.

The fee, as Spirit announced in April, is $45 per bag at the gate, or $30 if paid in advance. The airline has lowered fares by an average of about $40 to offset the fees, spokeswoman Misty Pinson said.

Atlantic City International Airport’s main carrier expects less carry-on volume and a smoother boarding process as a result. “It looks like this is going to speed things up,” Pinson said Sunday afternoon.

That unfortunately was not the case for folks trying to fly Sunday afternoon from Atlantic City to Orlando. Mechanical problems in Boston forced the flight’s cancellation and frustrated passengers who assailed the fee as an added headache.

“It’s ridiculous for a carry-on,” said Pat Spadafora, 65, trying to head back to Florida after visiting family in Cape May Court House. Her $300 fare was no cheaper than the previous time she made the trip, Spirit’s claims notwithstanding, she said. Spadafora lugged her carry-on suitcase and a brown paper bread bag out of the terminal, awaiting a replacement flight this morning.

Karen Salchow was the only one from the canceled flight to land a seat on the Orlando flight four hours later, thanks to a tip-off from her sister in the industry, she said.

“This is really the only problem I’ve had with Spirit,” the Toms River resident said of the cancellation. She said she didn’t mind the fee if a lower fare would make up for it.

Not everything passengers carry on a Spirit flight will cost them. Anything that fits under a seat — less than 12-by-14-by-16 inches — is free, as are food, books and other reading material, car seats and strollers, diaper bags, coats, cameras and umbrellas. And there are no weight restrictions.

Spirit began charging checked-bag fees in 2007. The first two bags are each $25, but as of Sunday, the third through fifth bags are each $85, down from $100.

Atlantic City’s is the closest airport even for people who live outside the region. Dan Reilly, 49, of Manasquan, Monmouth County, has flown Spirit out of Atlantic City about five times a year for 10 years. It’s a quicker drive than to Philadelphia, Newark, Kennedy or La Guardia.

Reilly wasn’t pleased about the carry-on fee, but, he said, “I’ll use them again. You’re stuck. There’s nothing else to do.”

John Allen, of Fair Haven, Monmouth County, said he would look to take Jet Blue out of Newark or Southwest out of Philadelphia on his next trip to Florida, rather than Spirit.

“Atlantic City (airport) used to be a great trip. Now it’s more of a hassle,” Allen said.

While would-be Orlando passengers stewed, Mary Flack, 51, of Lake Lure, N.C., awaited her charter flight home after a beach-and-casino weekend. She flies Delta when she goes commercial, but ships her luggage by postal service, saying it saves money.

“I don’t like air luggage fees,” Flack said. “I hope they go with that law to make them show their fees.”

In December, U.S. Sen. Bob Menendez, D-N.J., proposed requiring those selling airfares to display all fees and surcharges “in reasonable proximity to the price of the ticket.” That bill remains in committee, as does a bid to make airlines pay the same 7.5 percent tax on carry-on fees they already pay on ticket prices.

Asked whether she expected other airlines to follow Spirit’s lead with carry-on fees, Salchow replied, “I hope not. Probably. Things change.”

The Associated Press contributed to this report.

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