Frontier Airlines will add flights to 10 new cities from Philadelphia this spring, among 42 new routes nationwide announced by the Denver-based airline on Thursday.

Flights from Philadelphia International Airport to New Orleans; Raleigh-Durham, N.C.; and Indianapolis will begin April 14. Nonstop flights to Nashville, Cleveland, and St. Augustine, Fla., will start April 15.

Frontier will begin flying to Cincinnati on May 13, to Austin, Texas, on May 15, and to Kansas City, Mo.; and Milwaukee on June 2.

One-way fares on the new routes were advertised on the airline's website, flyfrontier.com, as low as $59 to $99 Thursday. Future fares will depend on the day of the week, the season, how full the flight is, and how far in advance a ticket is booked.

Frontier, which uses the slogan "Low fares done right," said its base fares are 50 percent to 70 percent lower than "industry average" ticket prices on the major airlines.

Though it offers lower base fares, passengers on Frontier pay extra for everything: a carry-on bag in the overhead bin; advance seat assignments; even a soft drink on the plane.

Two routes, St. Augustine and Austin, are not currently served by any airline directly from Philadelphia International Airport.

Cleveland, Kansas City, Milwaukee, New Orleans, and Indianapolis now are served only by American Airlines, which has a hub and 76 percent of the flights in Philadelphia.

Cincinnati, Nashville, and Raleigh-Durham are served by more than one carrier.

"This is exciting news to passengers in the Philadelphia region," said Philadelphia airport CEO Chellie Cameron. "When competition increases, this typically translates to lower fares and makes flying a more attractive and affordable option."

When low-cost carriers such as Frontier and Spirit Airlines begin flying a route, ticket prices drop. Other airlines will match the competitor's lower fares.

"Philadelphia is one of the cities where we have seen super-low fares on routes that compete with Spirit and Frontier," said George Hobica, founder and president of Airfarewatchdog.com. "You can fly Philadelphia to Miami on American for $89 round-trip before Feb. 12. Las Vegas was $75 each way nonstop. Even Southwest is lowering fares to compete with Spirit and Frontier."

Flights to Austin, Kansas City, Milwaukee, New Orleans, and Raleigh will operate Tuesday, Thursday, and Sunday. Flights to Cincinnati, Cleveland, Nashville, and St. Augustine will run Monday, Wednesday, Friday. and Saturday. Frontier did not say which days the Indianapolis flight will operate.

Frontier's flight schedules work for leisure travelers who can adjust their trips to the days the airline flies. But for business travelers, an extra hotel night costs more than any savings on the airfare.

"Southwest offers much better value when you consider you have to pay for everything else on Frontier after your flight fare," said frequent traveler Gregory F. Johnson, from Milwaukee. On Southwest, the first two checked bags are free.

This winter, Frontier operates nonstop flights from Philadelphia to Cancun, Mexico; Montego Bay, Jamaica; Punta Cana, Dominican Republic; and Orlando, Fort Myers, Miami, and Tampa, Fla.

On March 17, Frontier will begin a daily nonstop flight between Philadelphia and Denver.

Last year, Frontier flew seasonally from Philadelphia to Atlanta, Charlotte, Chicago, Houston, and Minneapolis.

The Atlanta and Minneapolis flights "aren't coming back" because of lack of demand, said airline spokesman Jim Faulkner.

Frontier, which had flights to 11 cities from Trenton-Mercer Airport in Ewing, N.J., last summer, dropped seven of the "seasonal" routes, which were to cold-weather destinations.

Frontier now flies from Trenton to Fort Lauderdale, Orlando, Palm Beach, and Fort Myers, Fla.

Faulkner said a Frontier decision on which seasonal flights will return to Trenton "hasn't been made yet as we continue to look at the summer schedule."

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