because the united states "nation builds" and acts as the global police force for third world shit holes. that requires boots on the ground. also you still need basic infrastructure in place for drones in some places. but mainly it's the whole world police thing. why do you think isreal has one for the most powerful air forces relative to country size, they just bomb sand niggers back to the stone age and call to say. they aren't trying to civilize them and don't care about "fighting fair"
United States