The movies have done considerably accurate descriptions of the events of execution by means of hanging. Once the trap door opened the person sentenced to death fell to the ground. Before they hit the noose would catch hold of their head, when all goes well snapping their neck killing them almost instantaneously. But in this imperfect world the victim may survive the initial drop and have to literally hang around and wait until they lost consciousness and died of suffocation.
Death by Hanging is still a lawful means of execution in the states of Delaware, New Hampshire, and Washington. However it is reserved as a substitute means if the Lethal Injection is ever held as unconstitutional or cannot be administered.