In two applications to the US Department of Transportation’s Air Carrier Licensing Division earlier this month, AirTran argues that of the three carriers designated to operate the DEN-SJD route, two of them – Republic and Frontier – are owned by the same company, Republic Airways, and that only Frontier is offering scheduled services on the route.

“In a limited entry market such as this, there is simply no justification for allowing Republic to continue to hold separate and unused authority that would block AirTran’s entry and competing service,” Robert W. Kneisley, associate general counsel for  Southwest stated in the airline’s latest application on November 21.

Under the current US-Mexico Air Transport Agreement, up to three US airlines can operate between DEN and SJD, with United, Republic and Frontier holding the rights until 2014, AirTran said.

According to AirTran, Republic has not operated the DEN-SJD route since April 14, 2008, when it ended services after just a year of operating them. It said that even after revoking its authority, Republic could still enter the market through a codeshare with Frontier.

In its November 2 application, AirTran stated that if it was granted rights to operate the route, it would it would offer a daily service from November through to April, falling to twice weekly from May through October, with a Boeing 737-700 in a 137-seat configuration and was prepared to “commence flying in the DEN-SJD market as soon as all regulatory approvals are received”.

To support its application, AirTran enclosed a letter from Kim Day, manager of aviation at DEN, urging the Department to approve the application.

With Southwest, which owns AirTran, ranking as the second largest airline at Denver, this could provide “substantial connecting opportunities allowing passengers from across Southwest’s network to benefit from the proposed Denver–San Jose del Cabo service,” Day said.