Interesting you say that, CAluv...I've noticed that, as well. Other than two extremely late overheads about 12:30 AM and 1:15 AM the night before last...not sure if you were still up and heard them or they were directly over my side of the freeway, perhaps...
But it's definitely been much quieter than normal. I had noticed it but wondered if I just somehow wasn't hearing them and they'd changed their routes and weren't quite as far inland as normal. Since you aren't noticing them either, then either they went way further inland or else something has changed in our neck of the woods.
I did hear the late ones two nights ago. It's kind of an eerie quiet now compared to what was going on.