I was just reading that four major USA airlines cancelled their flights to Israel - indefinitely - and before any order came out from the FAA. So I’m thinking that this action by those four major USA airlines pushed the FAA into acting. Of course I can’t be sure that it did, but those four major USA airlines did it on their own.
It doesn’t work that way. Delta operations started the ball rolling, mostly likely in close coordinated with the FAA (every airline has risk assessment teams that work closely with their local FAA office). UAL’’s afternoon flight was next, after the FAA issued their NOTAM. US Airways cancelled only tonight’s flight after the FAA issued their NOTAM. US Airways is going day to day.