Paulding County and Delta Air Lines, adversaries in a battle over a second commercial airport for Atlanta, have each asked the U.S. Department of Transportation to investigate the other.

Paulding county commission chairman David Austin and Propeller, the county’s development partner for the commercialization of the Paulding airport, wrote in an Oct. 21 letter that Atlanta-based Delta’s “sharp-elbowed anticompetitive conduct” is designed to prevent a second airport from being developed, to intimidate potential competitors and to ensure that low-cost competition doesn’t enter the market.

The DOT said it is looking into the matter.

Meanwhile, Delta’s chief legal officer Ben Hirst on Wednesday wrote to the DOT about the airline’s concerns about privatization of the airport at public expense, compliance with Federal Aviation Administration requirements and other issues. He called for the DOT to “fully investigate the proposed transaction.”

On Thursday, the DOT issued a statement saying: “A number of entities have raised questions and concerns about the possible commercialization of Paulding, and we are looking into those questions and concerns. We are not focusing on any particular entity. We are simply trying to assess the facts.”