Some of them were in the air, but most were on the ground, rushing around the way ants do- a few having squirmy, dangerous-looking sex.
I read up about them afterwards. They come out of the ground in warm dry weather, have a bit of a rave, hook up with a partner and then- if they're female- drop off their wings and scurry back underground to lay their eggs. I don't know what the males do- probably just keel over and die.
I reckon they got things done in the nick of time because it rained heavily over night.