Southwest Airlines took another step in completing its integration with AirTran, announcing Monday that customers can purchase tickets to all 97 destinations served by the two carriers in a single transaction.

The newly connected booking network will handle sales for all flights starting April 14.

"With a connected network, we can offer customers more itineraries, more destinations, more low fares," Bob Jordan, chief commercial officer at Southwest Airlines and president of AirTran, said in a statement.

The network will allow customers to add an international AirTran flight to a domestic Southwest itinerary. It also allows customers to earn points in either loyalty program no matter which carrier they fly.