
My personal experience with cats is that they go through "must get outside!" phases. We currently have one cat in a "must get outside!" phase, and one that just went out of said phase... thankfully it seems like it's mostly only one at a time with these guys. The only thing we really do is toss them away from the door, or nudge them away, or find a toy and toss it for them to chase... or just snatch them up really quick when they DO get out. Eventually they seem to lose interest in whatever it was they wanted outside and it becomes less of a problem for a couple of months.
The spray bottle idea is a good one, though like I think people already mentioned, keep in mind that not all cats actually care about being sprayed. You could also convince the cat he's starving by either making sure his food bowl is empty or taking up the food bowl about an hour or two before you need to leave. Then, right before you leave, become his savior and distract him with the food he so desperately needs because CAN'T YOU SEE HE'S WASTING AWAY?! I often leave my guys without food overnight, so they all swarm when I feed them in the morning and I can get out of the door unmolested.
The spray bottle idea is a good one, though like I think people already mentioned, keep in mind that not all cats actually care about being sprayed. You could also convince the cat he's starving by either making sure his food bowl is empty or taking up the food bowl about an hour or two before you need to leave. Then, right before you leave, become his savior and distract him with the food he so desperately needs because CAN'T YOU SEE HE'S WASTING AWAY?! I often leave my guys without food overnight, so they all swarm when I feed them in the morning and I can get out of the door unmolested.