Possibly either termites or ants. When winter ends and the spring-like weather first comes, flying termites and ants will break out of their winter nests and search for food and new locations to inhabit. With the spring-like weather we've been having, it's not uncommon for it to trick these animals into thinking it's time to come out. It's called swarming and that's why you see them everywhere. Literally hundreds and up into the thousands can come out of a single area. I did pest control (termite work) for 4 years in the late 90's is how I know of this. Later, QD.