Looking out of the window today, I spotted a few small birds flying over the trees. Instead of just flying in a straight line like the crows do, these were swooping, diving, circling and generally putting on an aerobatic display.
It was incredibly difficult to get a photo of them, so this is one I took on a previous occasion, when they were flying around the country lane I was walking along.

According to the RSPB site, Swifts even sleep while flying! I’m amazed they can perform such tight turns and dives without crashing into the other birds, let alone sleep while flying.