Regularly scheduled commercial flights are expected to return to the Florida Keys Marathon Airport next month.

Regional carrier Cape Air will touch down in the Middle Keys on Dec. 19 and begin its daily service to Southwest Florida International Airport.

The carrier's security code-sharing agreement with Continental Airlines will allow Florida Keys passengers to fly beyond Fort Myers without having to go through security and recheck their luggage.

"We are fully out for sale," Cape Air Vice President of Planning Andrew Bonney said.

As of late October, the Marathon flight schedule was added to Continental's reservation system, allowing it to be booked via the Internet or through phone reservations.

The airline makes three round-trip flights between Marathon and Fort Myers each day, with each way costing about $100, in addition to the cost of the flight to the passenger's final destination.

As for booking numbers, Bonney said it is too early to tell how popular the flights are.

"The booking curve is usually three weeks," he said. "We also haven't started our marketing blitz."

Cape Air is the second carrier to attempt to make use of profit guarantees to sustain business. The county and private fundraisers ponied up $250,000 for Cape Air and $500,000 for Delta Air Lines, which flew daily flights from Marathon to Atlanta in the first half of 2007.

The difference between Cape Air and Delta is the former's service will be seasonal, ending in April, whereas the latter tried to operate year-round. Much of Delta's profit guarantee would have been chewed up in the traditionally slow summer months. The airline ultimately never received the money, however, because it was contingent upon Delta providing service for a year, which it didn't do.

Passengers flying out of Marathon will not undergo the traditional security screening process. Due to the limited traffic using the terminal, the Transportation Security Administration has decided to use reverse screening, which means passengers' bags will be checked at Fort Myers before they are released to a connecting flight.

rbusweiler@keysnews.com