It should be noted that aircraft and all other vehicle and personel movements on an airport are controlled from the airtraffic control tower by air traffic controllers or directly by individual flaggers, as directed from the tower. Or at least thats the way it is supposed to work, and of course the operation at a place like LaGuardia is more complex, and will have specialists and multiple zones. What will put an extra edge on this is the whole ICE thing, and airport chaos pulling the roof down.