I don't suppose the node bonuses stack?
Oh wait, nodes are the healing improvement... does that mean I'd need the enemy to be next to a node, or that I'd need one next to the city they are based in?
Next to the city where the aircraft are based.
I'm actually not sure whether they stack, something I still have to check. But getting +20hp on all 3 aircraft each turn, you don't often need more than one.