What would be the effect of several large Passenger Pigeon flocks on Commercial and General Aviation in the Midwest US? Not to mention driving conditions in and around a town where a flock decided to land.
Well, IIRC it was only a problem twice a year along predictable routes so you could plan accordingly. It would only be an issue at takeoff/landing if/when the flocks were clouding over the airports (in flight you'd be well over the flocks). I could see if the flocks swarm the airport you could delay/cancel/divert flights just as you would for a massive thunderstorm. When/if *radar appears the flocks would show up.