For every acton there is an equal and opposite reaction.
For every action there is an equal (in size) and opposite (in direction) reaction.
Moving Balloon
As the air rushes out of the balloon it pushes the air out side of it downwards and also accelerates the air. Since the forces are acting against each other the air outside of the balloon is also pushing the balloon upwards as it goes downwards, accelerating the balloon through the air. The size of the force which was exerted onto the air by the balloon is equal to the size of the force which is exerted to the balloon by the air.The direction of force on the air was downwards and the direction of force on the balloon was upwards as you can see both forces were exerted in opposite directions. In conclusion this is why a balloon flies up when the air is released out of it.
Someone Sitting On A Chair
This is a good example of opposite and equal forces acting on someone sitting in a chair. She is able to sit down on the chair and not float around because of gravity and she is not able to break through the chair because of its up thrust. These forces are both acting on the same object and because they are opposite and equal in size, the forces allow you to sit on the chair.
Opposite and Equal Forces On A Plane
Opposite and equal forces such as friction and air resistance and the drag of the plane, the gravity of the plane and the lift of it, keep the plane balanced. Without these opposite and equal forces acting on the plane it would be impossible for the plane to move in a straight line at a constant speed or stay at rest.
Pushing On A Wall
The person is trying to accelerate on a skateboard by pushing on a wall. The wall is pushed backwards, and because the forces are acting against each other the wall must also be propelling the person forwards. Both forces exerted by the objects are equal and the pushes are both in opposite directions. In conclusion you are propelled forward when you push off a wall because of the force the wall exerts onto you.