Delta Airlines is starting to feel pressure both in Washington and on Wall Street because of a little airport in Paulding County.

After letters from Paulding County Chairman David Austin and others, the Department of Transportation is investigating whether Delta may have had an undue role in the ongoing effort to keep low-cost flights from operating at Silver Comet Field near Dallas. DOT acknowledges it is looking into allegations of “unfair and deceptive practices” by the airline, including charges Delta is secretly funding ongoing legal opposition to commercial service at Silver Comet Field.

Delta has opposed the notion of service from a second metro Atlanta airport for approximately a year, after it was announced by Paulding County officials last November. Critics continue to claim that Delta has funded lawsuits, billboards and even politicians opposed to the advent of discount airline service at the single-strip airport ever since.

"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," said DOT spokesman Brian Farber in an email to WSB's Pete Combs.

There are even allegations that Delta was behind a series of burglaries at the homes of those who support commercial service to Paulding County.

Ironically, Delta’s opposition to the advent of airline service to Silver Comet Field is the exact opposite of what Delta is saying about a similar situation in a different state.

Earlier this month, Delta was told it would have to vacate its gates at Dallas Love Field in Texas. The airline put up a fierce fight, even threatening to sue the city of Dallas, TX, in order to remain competitive at Love Field. In this case, Silver Comet Field proponents say, Delta is fighting to keep competition out of a second Atlanta airport.

The informal DOT investigation appears to be worrying Delta shareholders, according to Reuters. The airline’s stock price was slightly down on Tuesday.