As part of a nationwide revamping of the air-traffic system, the Federal Aviation Administration has proposed changing air corridors in and out of Phoenix Sky Harbor Airport, the Valley's main airport and the sixth busiest airport in the nation. The officials are attempting to untangle crowded airspace about 200 miles northeast and northwest of the city.

Because such a large portion of the state's airspace is restricted to military flights, public flights are relegated to a small number of corridors in and out of Sky Harbor Airport. Some of those routes intersect near the cities of St. Johns, a rural town about 200 miles northeast of Phoenix, and Kingman, a rural city about 200 miles northwest of Phoenix.

By converting some of the current departure routes into arrival routes and vice versa, and by eliminating some routes altogether, the FAA hopes to reduce the aerial clutter.

But the new routes proposed would take planes over parts of the Valley that have never before had a great deal of overflights. The new routes would mean increased overflights for Carefree, Cavecreek and Fountain Hills, three suburbs of Phoenix situated on the northeastern corner of the Valley. Much of north Scottsdale and the north side of the McDowell Mountains would also have increased overflights.

In all, those areas hold the lion's share of the most upscale master-planned communities and multi-million dollar homes in the metropolitan Phoenix area. North Scottsdale and Fountain Hills have been one of the most popular areas for new home development in the past five years, and noisy overflight could hurt home sales or change development patterns.

Phoenix's Sky Harbor accommodated 35 million passengers in 2000 and expects to serve 58 million annually by 2015. The airport, which just opened a third runway late last year, is on pace this year to handle more than 650,000 flights.

The plan will be released to the public on Monday. The public will have 45 days to respond to the plan.