Rumor says that the site was Whiteman Airport in Pacoima, California. It is a small airport in the San Fernando Valley and has been around for a very long time.
A co-worker saw this episode and mentions that a Los Angeles Department of Water and Power Power Plant is in the background. He should know, as that is where we work.
As I have not seen this show yet, since hearing we are in the background I have started looking for it. If anyone is able to confirm this rumor, it would be greatly appreciated. In the meantime, my own search for this episode continues.