I bet you guys would be of the same opinion if a new flight path suddenly popped up over your home, decreasing it's value and your quality of life.
In the mid 90's I lived on the 7 ways at Rockdale, our rear balcony was on the flight path for Runway 07 at Sydney (before the parallel). A slab, pizza and deckchair and it was bloody great. the aircraft would be below 1000ft at that stage. A lot lower than the morons in Brisbane are complaining about.
Does it lower the real estate values? Bull**** it does, check any of the sale prices in the last year or so. You get used to the level of noise.