She will hold in custody until the plane reaches its final destination. Same is true if a passenger just decides to leave the aircraft before takeoff. Some countries just keep the person in ordinary office, some has cells. Don’t know about the USA. If a passenger just decides not to fly and causes a delay because of all the procedures that need to be taken, airlines do have right to charge the passenger for financial damage. I am not sure, but same must be true for drunk passenger as well. However, I have never heard any airline that used its right to do so.
So, except some harsh countries, overall passengers like that just waits a few hours until the plane lands, sign some documents and leave.
Edit: plus, don’t be bad. What if it was just the beginning of the trouble she was causing? What if there was already scared/sensitive people onboard? I have seen two people died from heart attack just because they were afraid enough in the aircraft. She needs to learn how to behave.