I have heard a couple of podcasts that had some very credible US pilots talking about this. I think detecting life on other planets or aliens here would be great (so long as they are not trying to kill me yada yada). But, the most down to earth explanation is signal/sensor warfare testing.
Bare with me for a moment. The web is part of the sensor array of a spider. There are species of insects that tap on spider's webs to send a false positive signal to the spider on the web that a tasty prey has become trapped. The spider goes over to where on the web the vibrations indicated the prey is trapped and bang the spider gets killed by the assassin bug.
https://www.bbc.com/news/science-environment-11628322
There is some evidence these signal warfare systems are being developed:
https://www.thedrive.com/the-war-zone/29505/the-navys-secret...
I think these are newest iterations of the Wild Weasel style of counter weapons:
https://en.wikipedia.org/wiki/Wild_Weasel
they could make drones go a fuel wasting wild goose chases etc. Or make the other sides drone defend the eastern front while you fly in from the west etc.
more signal warfare stuff:
https://en.wikipedia.org/wiki/Nulka