NEW CANAAN, Conn. -- The ambient noise around this upscale community's antique stores and fashion boutiques consists of idling SUVs and a few whooping children.

So the possibility that a stream of airline jets may soon be buzzing overhead -- albeit at altitudes of a mile or more -- has prompted outrage from community leaders, who say that the noise will harm schoolchildren, reduce property values and undercut the town's way of life.

"This is not the kind of town that will take this," says Judy Neville, a former first selectman here who leads local opposition to the jet traffic, gesturing toward perfectly manicured lawns and quaint clapboard homes.

The Federal Aviation Administration (FAA) wants to change jet routes to ease congestion over New York City and Philadelphia. In the process, it promises to reduce aircraft emissions, cut fuel use and lower average noise levels across the region. The effort is the best short-term hope to improve the region's delays, the agency says.

The plan has run into a loud buzz saw of opposition from dozens of communities in the heart of the densely populated East Coast, in a fight with profound implications for the future of aviation.

The battle has slowed implementation of the FAA's rerouting plan, making it difficult for the agency to attack airline delays that remain at near-record levels -- and raising questions about whether the agency can make further changes to improve the aviation system.