The large craft seemed completely oblivious to the hundreds (500+) AA shells bursting around the ship.
It appeared to have a protective force field as no damaged was inflicted on it.
There were casualties on the ground, at least 6 civilians died as a direct result of the Army's attack on the UFO. The untouched UFO then slowly made its way toward and then over Long Beach, before finally moving off and continuing on, unstopped.
The military generals were ordered by the government to claim that it was nothing but a large balloon that they could not shoot down. Left embarrassed, they eventually followed orders and lied about this craft being a balloon.