Frontier Airlines is continuing to add flights at Philadelphia International Airport. The carrier Tuesday announced nonstop service to two more destinations - Fort Myers, Fla., and Montego Bay, Jamaica - beginning Oct. 25.

Introductory one-way fares were offered Tuesday only: $49 to Fort Myers and $99 to Montego Bay. Going forward, fares will depend on the day of the week, the season, how full the flight is, and how far in advance the ticket is booked.

Denver's hometown airline began flying to three Florida cities last winter from Philadelphia, "and it's proven to be exactly what we expected," said Daniel Shurz, chief commercial officer. "There's plenty of demand, especially to leisure destinations."

The east-west routes to Chicago and Minneapolis this summer are doing well, Shurz said. "We're very confident about our added seats to international leisure markets this winter."

Currently, Frontier flies from Philadelphia to 10 cities: Atlanta; Cancun, Mexico; Charlotte, N.C.; Chicago O'Hare; Houston; Miami; Minneapolis; Orlando; Punta Cana, Dominican Republic; and Tampa.

Frontier also flies to 11 cities from Trenton-Mercer Airport in Ewing Township, N.J.

Since Frontier's first commercial flight from Trenton to Orlando in November 2012, the airline quickly expanded to 18 nonstop destinations from Trenton. It later discontinued service to some cities, including Cincinnati, Cleveland, Nashville, and St. Louis because of lack of customer demand.

"We're focusing in Trenton on routes and on markets that work seven days a week," Shurz said. "We're moving in the direction of flying the vast majority of our network on a daily basis."

The carrier recently discontinued flights out of New Castle Airport in Delaware.

Frontier has been remaking itself as an "ultra low-cost" airline. Base fares are cheap, but passengers pay extra to put a carry-on bag in the overhead bin ($30 at online check-in; $60 at the gate), for advance seat assignments ($6 to $11), and $1 for a soda on the plane. Water is free.

The airline filed for bankruptcy in 2008, was acquired by Republic Airways in 2009, and was sold in 2013 to a Phoenix private-equity and venture-capital firm, Indigo Partners. Over the last year, Frontier has been overhauling its route network and moving to a low-fare business model similar to that of Spirit Airlines.

When it begins, the Fort Myers flight will depart Philadelphia seven days a week at 5 p.m., except on Tuesdays, when it will leave at 5:30 p.m. and arrive in Fort Myers three hours later.

The three-days-a-week Montego Bay flight will depart Philadelphia at 7:30 a.m. on Sunday, Tuesday and Thursday, arriving in Montego Bay at 11:25 a.m.