Last Post: June 10, 2010:
Pimping my own video, I recommend you watch "Channel planning with 802.11n and DFS".
I outline a few things that may help. The short version is, if you test properly in your area, you can use UNII-2 if your system doesn't detect any radar.
Being close or far from an airport doesn't matter that much. Some airports don't even use 5 GHz and there are weather radars that will trip DFS that aren't near an airport. Proper testing (somewhat outlined in the video I think) is the way to go.