But 20 trucks full of gasoline get shot up within 10 miles of the airport? Wouldn't one Apache have been able to kill hundreds of them?
There could be several reasons for no air support. The attack helicopters could have been committed elsewhere or - as things had been peaceful up until this point - there would have been a lot of red tape involved. The unit had to be alerted for the mission and permission would be needed to use them in the urban area. For this someone “higher up” would have had to check out the situation personally, given the command (possibly as high as Centcom if not higher). The orders then would be passed back down the chain, op orders written up etc.
Remember that this has turned into a CYA operation.