Southwest Airlines (NYSE:LUV), which bought AirTran in May 2011, announced today that it will take the routes that AirTran operates in four cities and turn them into Southwest Airlines routes.

The changes will happen April 14 in nonstop routes servicing Charlotte, N.C.; Flint, Mich.; Rochester, N.Y.; and Portland, Maine. A limited-time fare sale is being offered to mark the change.

Southwest has already said that the AirTran operations in Branson, Mo. will change in March. AirTran operations in Allentown, Pa.: Harrisburg, Pa.; Huntsville, Ala.; Lexington, Ky.; Sarasota, Fla.; and White Plains, N.Y. were shut down in August.

Fool contributor Dan Radovsky has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Motley Fool newsletter services recommend Southwest Airlines. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.