We should fill fire suppression planes with water and just dump it on the columns as they approach. A harmless deterrent that shouldn’t cost too much to perform and it’s just water. A few drenchings with more planes in the sky and they’ll figure out that they’re not welcome.
Mis the water with skunk water...a strong deterrent.
Water cannon, rubber bullets, bean bag shot, and other non-lethal riot weapons, in mass.
Dousing them with salt water is even better - especially while they are walking beneath the hot desert Sun. Better still - load those chopper tanks with cow piss and feces.