Piston planes do, turbine planes don't. Unfortunately for small single engine planes, piston is still a lot more common and quite a bit cheaper than turboprops, though just like with airliners before, turboprops is (very) slowly becoming the norm for general aviation as well.
Even if aircraft are worse, I'd be curious how traffic factors in. Even a moderately busy highway would have several orders of magnitude more traffic than this community airstrip, I would imagine.
Do people fly for like, a trip to the grocery store? To work? Or is it for Sunday joyrides and the odd out of town trip?
I'm not an expert on pollution, but leaded fuel is extremely nasty stuff. There's a pretty substantial correlation between a big drop in violent crime and the ban on leaded fuel.
Here is a Forbes article... Mostly because it was the first to come up.
The theory is that lead is extremely bad for developing minds. Hence the roughly 20 year offset. Kids exposed to it grew up to be a little nastier. Fully formed minds aren't as susceptible.
Again, I'm not an expert, but I'd be shocked if breathing in lead wasn't really really bad.