As Southern California enters the tensest months of fire season, a looming issue could keep critical air assets used to battle the big blazes stuck on the ground, or force them to go long distances between drops. A lack of truck drivers is making it hard to move jet fuel around all of the West. Rural airports that double as air tanker bases in Montana and Idaho have already seen their fuel tanks run dry and had to send fire planes elsewhere for supplies. Now it looks like that problem could be migrating south to the Golden State.