Could be agriculture-related.
That’s my best guess, too. Mississippi has a big website on the virus and I find nothing about spraying.
Perhaps, but she said military helicopters
I was going to say either crop or mosquito spraying could be a possibility. Though I doubt the military gets involved in either operation of that nature. I can find no evidence of this claimed operation when I do a search. The only hit I get is some blog, and when you click on the link it actually brings up this post. 8>)