In the daily operations of on-the-ground forces, were there ALWAYS air support ready at hand / available?

I was watching the Oct 4, 2017 Niger Ambush documents, and in it there was a force of like 7 vehicles (half US) leaving a village, and when attacked no one radioed for help, and there was no air support that participated, despite the battle lasting about an hour (until near the end where the first radioing in was done). Could this have happened in Afghanistan too?