[John Beaman]

Some thoughts: This is from a friend who is very well versed is US Army tactics' history:

1. The USA rarely deployed AAA units with moving columns. We might place AAA batteries at sites such as crossroads, defiles. bridges, etc. Choke points or congested areas.
2. Most American vehicles armored or other wise were usually equipped with an AAA machine gun not to mention small arms such as M-1's, carbines, sub machine guns and the like. Unless a column was surprised or caught where it couldn't maneuver it should be able to scatter and minimize the damage.
3. Early war doctrine seemed to emphasize taking cover, spreading out and laying down as much fire as possible. An example might be an early war tank company (Shermans). With three platoons that makes 15 fifty cal machine guns for AAA plus the light platoon of M-5 Stuart's another 5 Fifty cals. Plus 2 for the Headquarters tanks and throw in 2 Jeeps a half track (ring mounted fifty) and 18 trucks (at least half with ring mounted fifties) and a tank retriever you can have roughly 30 AAA heavy barrel fifties for defense. This was assumed to offer adequate protection against strafing. And remember early war doctrine was formulated against slower and less powerful aircraft than we faced later in the war.