Plans for a second commercial airport in metro Atlanta have hit more turbulence, with local residents filing another legal challenge to the Paulding County airport’s plans to bring in airline flights.

The residents — who have raised concerns that the airport’s plans were made in secrecy without public input — argue that the Federal Aviation Administration’s environmental approvals for taxiway and runway expansions were granted without analyzing the effects of commercial airline service.

The Paulding residents — Susan Wilkins, Anthony Avery and five others — “will suffer adverse environmental effects from the Airport’s expansion” and thus have an interest in the FAA decision, states the petition for review filed this week in the U.S. Court of Appeals in Washington by law firm Sidley Austin LLP.

At the heart of the challenge is the argument that the Paulding County Airport Authority “mischaracterized the real scope of the total project and the nature of the work,” according to a related request for an administrative stay sent to the FAA by Sidley Austin.

The stay, which seeks a halt in all work on the projects and a directive to conduct an environmental analysis, requested an FAA decision by Nov. 18. When that date passed without action, Paulding residents took the next step of filing a petition for review.

The FAA through the Georgia Department of Transportation approved the airport’s runway and taxiway projects in late September, just before the airport went public in early October with its plans to attract commercial airline service

But Sidley Austin, in its letter requesting a stay, said the approvals “did not address or even mention commercial passenger service,” and did not involve noise or air quality analyses based on the rationale that the projects would not lead to increased airport operations or different aircraft.

GDOT, in a statement emailed to The Atlanta Journal-Constitution, said it “takes seriously its responsibility to ensure the appropriate environmental review process … and will continue to work with FAA, Paulding County and its citizens to ensure any concerns are fully addressed.”

Paulding airport director Blake Swafford said if anything was done incorrectly, “it’s something that we’ll address.” But he also said the runway and taxiway projects are improvements that had been planned for years. “They are not new projects that were developed because of the commercial (flights).”

Meanwhile, Delta Air Lines is stepping up its opposition to the idea of a second metro Atlanta airport.

Paulding airport officials have said the plan is for just a few flights a week initially. But Delta spokesman Trebor Banstetter said, “Once commercial service is established at a secondary airport, no one can guarantee that it won’t grow and become a much larger airport, no matter how small the initial service might be.”

Delta argued that secondary airports siphon traffic flow from hubs “and ultimately reduce the number of flights and destinations that can be successfully operated.”

Delta made its argument in a letter released today in a response to Paulding County Commissioner David Austin, who in his own letter last week to Delta CEO Richard Anderson accused the carrier of orchestrating an opposition campaign to the Paulding airport’s plans.

The Delta letter, signed by senior vice president of corporate real estate Holden Shannon, said Delta is “mindful of the potential negative impact a Paulding County passenger airport could have on county taxpayers,” adding that the airline has nearly 800 employees in Paulding County.

If the court grants the Paulding residents’ petition, it will review the FAA approvals and decide whether they should stand.