I actually tried doing it recently. I was working on Northrend loremaster and flew over WG and thought, “hmm 5 minutes to the next battle. Why not?”
So annoying. Horde was defending and I could find barely any NPCs to kill to rank up to make vehicles. There was some horde players running around somewhere but by the time I would get to where the game said they were attacking they were gone. I think it took 10 minutes just to get to corporal and 1 catapult clearly wasn’t going to knock down a wall.
I finally realized right near the end that you can fly for little bursts at a time and I ended up flying right into the center of the fort and the NPC’s were much tougher there, but there were a lot of them. I think next time that’s what I’ll do from the start. Rank up to Lt. Then go get a wall demolisher tank and have at it. Even then I’m not sure I could win it in 20min solo.