This was once taught as a valid air defense tactic in the infantry. It was in the field manuals. We also designated an air guard for every vehicle and even for foot patrols. We did not assume air superiority. We now have a lot more weaponry and countermeasures to counter this threat, but the threat of drones is growing just as fast if not faster. Sometimes, you have to make do with what you have at hand.
In the late 70s every infantry battalion of the 25th ID spent a month on the Pohakuloa Training Area on the Big Island of Hawaii. We did a lot of our live fire training there. Part of that training was each company shooting at a series of BATS (ballistic aerial targets) as they flew past our defensive positions. The most effective method to engage these targets was for the M-60 machine gunners to establish intersecting streams of fire leading the target. All riflemen would concentrate their fire on the intersecting streams of tracers. Normally the BATS would be recovered and we’d see how many holes we made. The BATS were made to absorb a lot of hits. On two occaisions, our company, once my platoon alone, shot the damned thing out of the sky before it could fly past our defensive positions.
I don’t know if this is practiced anymore. It should be.