Refueling KC-10 overhead, LCF outbound
Apparently, I live right under a designated aerial refueling route.
I looked up and saw two airliners flying perilously close until I realized they had to be refueling. It was clear the tanker was an KC-10, but it took me a while to research that the plane being fueled was a USAF RC-135. The larger nose and broad pods on the side were the giveaway.
Very cool to see this pass overhead, though it was pretty high up, pretty much at the limiting range of my optics (400mm f/5.6 Sigma + 2x TC)