Bringing a last-minute carry-on bag to the gate will cost you $100 on Spirit Airlines later this year.

The airline, which bills itself as an "ultra-low-cost" carrier, said it will increase fees for baggage and other services on Nov. 6.

In the Philadelphia region, Spirit operates out of Atlantic City International Airport, the only scheduled carrier now flying from that airport.

The fee hike drew new criticism for Spirit, already buffeted this week by its initial refusal to refund a $197 ticket bought by a dying Vietnam veteran who said his doctor told him he was too ill to fly. On Friday, Spirit's president and chief executive officer, Ben Baldanza, relented and said he would refund Jerry Meekins' fare and make a $5,000 contribution in his name to the charity Wounded Warriors.

Spirit, which advertises one-way ticket fares as low as $19.80, makes much of its money from fees on non-ticket items, such as checked and carry-on luggage, seat assignments and upgrades, and snacks and beverages.

Its average one-way ticket revenue was $76.65 per passenger in the first three months of this year, down 7 percent, while its average non-ticket revenue was $51.68 per passenger, a 21.3 percent increase over the same period a year earlier, the airline reported Tuesday in its first-quarter earnings statement.

Net income for the airline in the first quarter was up 197 percent, to $23.4 million.

Baldanza attributed the rise to "robust demand for our ultralow base fares with a range of optional services for a fee."

But Kate Hanni, founder of FlyersRights.org, a passengers' advocacy group, said Spirit's fee increases "are so onerous, they're going to lose customers."

She said that Spirit employees told her that "every day, people are left at the gate because they're unwilling the pay the fees or they don't have the money."

The increases in fees announced by Spirit this week will include $100 for carry-on bag fees at the gate, up from the current $45; $35 for a carry-on noted during an online reservation, up from $30; $50 for a carry-on paid for at the airport counter, up from $40.

"We don't want any of our customers to wait until they get to the boarding gate to pay for their carry-on bags as this delays the boarding process for everyone," spokeswoman Misty Pinson said in a statement. "We expect that our new $100 fee charged for those who wait until they get to the gate will ensure that customers purchase their bags before arriving at the gate."

Any bag that needs to go in the overhead bin is considered a carry-on. A small bag that fits under the seat is free.

Spirit is one of two airlines, along with Allegiant, that charge for carry-ons.

Last year, the Miramar, Fla.-based airline was fined $50,000 by the U.S. Transportation Department for advertising $9 fares without clearly disclosing the associated taxes and fees.

Contact Paul Nussbaum at 215-854-4587 or pnussbaum@phillynews.com.