Low flying airplanes, helicopters; I never used to pay that much attention. Post 09.11, and my initial thought is always the worst.
Just (5-10 minutes ago) saw a military fighter jet booking it across the Cumberland Valley (just west of Harrisburg, PA) beneath a low cloud layer on roughly a North East heading . . . this is not a "normal" thing to see here . . . we get military helos and big aircraft, but not much by way of fighters (except for when TMI was on high alert) . . . not sure what it means, but when I saw it I came back in and got on FR as soon as I could . . .