For the first time ever, Denver International Airport had no major noise complaints in 2008, after having one each (which costs the airport $500,000 a piece under a legal settlement of the issues) in 2005, 2006 and 2007. Some prior years, there were as many as twenty-four instances per year.
Neighors did continue to lodge 942 noise complaints (still down from last year by 12%), although 54% of the complaints came from just five families.
The Denver Post story, linked above, offers no insights on what DIA did to reduce noise, or what the circumstances of the five unhappy families are in this situation (e.g. if they were also the five closest families, simply buying out their properties and converting them to uses that aren't noise sensitive might make sense). DIA traffic is not markedly down, and no particularly notable models of aircraft have discontinued service in that time period.