Give Him Space
"Cats can hold a bad mood for a long time, an hour or more," Estep says. If he's in a snit, don't make the first move, he advises. Instead, learn the Best Ways to Calm a Cranky Cat.
"Let him approach you." This is especially important if your cat's aggression was provoked by the sight of a strange cat--one he can't reach. If he's unable to attack the target, he's likely to go for the dog, another cat in the house, or a nearby human