Quick defensive breakdown to show how Grass/Ghost is better defensive typing than Grass/Flying.
Grass/Flying resistances: Ground (immune), Grass (x1/4), Fighting (x1/2), Water (x1/2)
Grass/Flying weaknesses: Ice (x4), Rock (x2), Flying (x2), Poison (x2), Fire (x2)
TOTAL RESISTANCES: 1 immunity...