Southwest optimizes Routes after Merger with AirTran .

Southwest Airlines Co. said Friday that it would keep flying to 22 cities served by AirTran Airways but end flights to six others — raising the final cut list to 15 AirTran locations — as it combines the two airlines.

The dropped cities are smaller than typical Southwest markets and include Allentown, Pa., and Sarasota, Fla. Southwest said it couldn’t afford to serve such markets with today’s high jet fuel prices.

The decision ended months of suspense after Southwest bought AirTran in May. AirTran served 69 cities, including many also served by Southwest.

Besides the overlapping cities, the 22 non-Southwest destinations that the company will keep include airports in Mexico, the Caribbean and the Midwest and eastern half of the United States. Among them: Charlotte, N.C.; Memphis and Richmond, Va.

Outside the U.S., the airline will serve Cancun, Mexico; San Juan, Puerto Rico; Punta Cana, Dominican Republic; Montego Bay, Jamaica; Aruba; Bermuda; and Nassau, Bahamas. It will also keep Mexico City, where AirTran plans to begin flying in May 2012, and San Jose del Cabo, Mexico, where AirTran has set a June 2012 launch.

Southwest and AirTran operate as separate airlines, but Southwest intends to combine the two starting this year