Sorry I just noticed this posting and I'm also in the STL area.
I think I could of been helpful during the start of Camponotus Flights.. I found my 3 queens all in the same day, 2 in South County and 1 in Wildwood, but this was back in late May. But good news is they're still flying pretty aggressively, I haven't been searching lately, but on my walk today at a local park I found a couple dead Queens along the way around noon. I think I've had the best luck finding Camponotus just before the sun sets and after dark.
T. tsushimae is starting to fly very heavily, like BMM says search early in the morning just after sunrise. I've been keeping an eye out for pharaoh ants as well. Unfortunately if you're not familiar, most queen will be killed moments after they land from their flight. I've actual rescued a few Queens that were under attack by other colonies of the same species. If you have a swimming pool that isn't heavily chlorinated you can save queens from the water, but from my experience the chemicals in the water prevent survival in most. I guess it depends how long they took a dip for..
I'll keep posted here when I find something else interesting, and I am happy to mention that I've been seeing Pheidole also known as big headed ants in SoCo area. I will update if I happen to catch their flight, that is one I'm excited for!