ARVN reinforcements. Hah, they'll conduct a 'search and avoid' patrol. The ARVN was well-known for letting the VC know where they'd be patrolling to avoid any unfortunate hostile fire incidents.

One option that exists is calling up a Mike Force (SF officers and NCO's + highly trained Montagnards trained as a strike force) out of An Khe or Pleiku for on-the ground search and rescue or for reconnaissance. They're highly mobile and therefore easy to bring in on the move, and the Montagnards actually fight. (Some of the best troops of the entire war.) In any case, if there's any sort of combat going on at all, and they see the movement, that would mean that they're going to be putting Bird Dogs overhead, possibly Skyraiders if they're moving ARVN troops, since the VNAF flies Skyraiders with the USAF often advising.