The Colorado Court of Appeals ruled that courts can’t compel an airport owner to limit noisy training flights but it sent back a related claim about lead pollution for more scrutiny, highlighting limits on local power over aviation.

The essence of the Thursday decision in Town of Superior v. Board of County Commissioners of Jefferson County is that judges lack authority to force Jefferson County, which owns Rocky Mountain Metropolitan Airport in Broomfield, to use its authority to restrict flights.

The court affirmed federal preemption of noise regulation, saying local mandates would intrude on national airspace rules, but reversed the dismissal of the lead emissions part. It remanded the matter to the district court to determine whether restricting flights for pollution-related reasons counts as a preempted emissions standard under federal law that prevents local control.

The case began when Superior and Boulder County sued Jefferson County in 2024, seeking to halt “touch-and-go” operations — repetitive takeoffs and landings — over noise and lead concerns from aviation fuel, and centered on Superior’s Rock Creek subdivision in Boulder County.

The subdivision wasn’t developed until the 1980s — long after the airport opened in 1960 — so people knew about the airport, said Jefferson County in court filings.

Jefferson County has stood firm against limits, arguing in a February 2024 federal court filing that the complaints don’t hold up. The county maintains compliance with FAA standards through its voluntary noise abatement procedures, which include pilot guidelines to minimize impacts, such as using the primary east-west runway at night to avoid overflying homes under the shorter crosswind north-south runway.

It has no plans to reduce flights for noise reasons, focusing instead on education and a federally funded noise study started in 2025 to map levels and suggest fixes.

A 2022 Boulder County court order invalidated nine navigation easements in Rock Creek that barred complaints about aircraft operations over the community. Those agreements, dating to the 1980s and 1990s, hinged on noise staying below a 60-decibel day-night average sound level from the airport’s 2000 master plan, but the judge found that cap was exceeded.

The appeals court cited a 1973 U.S. Supreme Court ruling holding that federal law alone governs airplane noise for national consistency. While airport owners like Jefferson County can choose to impose restrictions under their authority, courts can’t make them do it — that would amount to local regulation of airspace.

Regarding lead pollution, the appeals court noted the need for a deeper analysis under Section 233 of the Clean Air Act, which bars states and localities from setting their own aircraft-emissions rules unless they mirror federal standards. Section 231 gives the EPA sole power to set those standards after its October 2023 finding that lead from aircraft engines endangers health.

Aviation organizations, in an October 2023 letter to Colorado’s attorney general, stressed this federal exclusivity, saying local actions could disrupt aviation without solving concerns. The EPA’s finding, they added, requires national coordination, not piecemeal local fixes.

Jefferson County has pushed back on the lead contamination claims, pointing to environmental testing in Superior from 2023 and 2024 that detected no airborne lead and minimal surface traces not tied to planes. In a May 2023 letter to Superior, the county outlined its voluntary plan to phase out leaded fuel by 2027 — three years ahead of the FAA’s 2030 deadline — with incentives like rent reductions for flight schools to offset certification costs.

Multiple news sources report that as of February 2026, FAA-certified UL94 unleaded fuel is now available at the airport via a new tank, with two flight schools committed to using the new fuel.

Superior’s December 2023 response letter demanded action anyway, claiming the county must address health and safety issues caused by rising flight numbers. The town argued that state law gives landowners rights to the airspace above their property. Colorado laws on the ownership of airspace vest title in the owner of the surface below, but “subject to the right of the flight of aircraft.”

Federal law puts the FAA in charge of the higher airspace for safe flying nationwide. FAA rules say planes must stay at least 500 feet above open areas or 1,000 feet over towns, unless taking off or landing.

The airport’s location on a mesa about 100 feet above Rock Creek homes means approach paths are higher over the ground than they appear, the airport says, reducing noise and emissions impact.