Internal documents indicate Federal Aviation Administration employees felt political pressure to approve a wind farm planned off Cape Cod.
The papers, obtained by opponents of the Cape Wind project, indicate it was approved amid internal disagreement over the best way to stop the turbines from interfering with radar and compromising airplane safety.
One FAA engineer wrote he doubted air traffic control could stop certain small aircraft flying nearby from hitting a turbine.
But the FAA says employee opinions expressed in internal documents aren't agency policy. It says its evaluations on how obstructions will affect air traffic are based on safety and the available ways to reduce risks.
A Cape Wind spokesman says extensive FAA review in the 11 years since the project was proposed shows it doesn't pose aviation hazards.