Why don't airplane owners get rid of those noisy jets?
Aircraft owners manage their transportation budgets very much like automobile owners; they trade vehicles when it is economically advantageous to do so. For the commercial service airline fleet, the FAA mandated a phase-out program designed to provide noise relief without imposing an undue economic burden on aircraft operators. Currently there is no legislation to require "Hushkits" on jets under 75,000 lbs., which is the type of aircraft that operate at Scottsdale Airport.
Scottsdale Airport - Administrative Offices
15000 N. Airport Drive, suite 100
Scottsdale, AZ 85260
Aviation staff (PDF)