LBJ was newly sworn in while being flown back to Washington.
They needed a local TX judge to make it official.
They took off right after that.
As to the rest, it is unbelievable, but necessary to see what the current POTUS limo has.
Remember when the limo got caught up on a speed bump a couple of years ago? it's a very heavy tank like vehicle.
There is an actual compartment to seal off the President if the car gets blown up. God forbid.