Answer:
The action force is the rocket pushing out the "hot" gases produced by the engine. The reaction force is the hot gas pushing back on the rocket propelling it into outer space.
And....
The reaction force is the hot gas pushing back on the rocket propelling it into outer space. There is no need for air to push on because the hot gases produced by the rocket allow the action and reaction forces to operate. These two forces are equal and opposite (action-reaction) forces.
Hope this helps you!! - Astralyradele