The best way to check that is by selecting the aircraft you need the range for, then click move, and hover over the dot of the province you need the range for. You'll see the "circle" (actually it's an egg, but hey) AS IF your aircraft was based there. You can then see easily if a candidate dot is or isn't in that circle.
Unfortunately this doesn't work when you're refuelling, (dis-)embarking, or driving around in a truck.
