The forces described by Newton's third law have a big part to play in creating aerodynamic lift.

For quick review, Newton's third law is usually described as, "For every action there is an opposite and equal reaction." Like all learned scholars of the time, Newton wrote his book in Latin, and Lex III (Actioni contrariam semper et æqualem esse reactionem) is more accurately stated as, "To every action there is always opposed an equal reaction." His example was, "If you press a stone with your finger, the finger is also pressed by the stone."

I find that flight students often have a hard time understanding how Newton's third law can be part of the intricate ballet of forces that lifts a 1.23 million-pound Airbus A380—or a Cessna Skyhawk—off the ground.

Ironically, there are three ways:

First: Your wing has a curved top surface to leverage the forces of differential pressure detailed by prominent eighteenth-century scholar and scientist Daniel Bernoulli. The question of how much this pressure differential contributes to lift is for another day, but know today that as air moves over the wing, it flows downward as it sides off the trailing edge, and, yep, the opposite force of down is up.

Second: Wings are angled a bit to the oncoming air. As the wing moves through the air, the underside strikes those molecules and forces them downward. This compounds the equal and opposite reaction, forcing more air down and generating a corresponding upward lifting force on the wing.

And third: Once in flight, the wing, pulled downward by gravity, pushes down on the air below it, much as Newton's finger pressed on the stone. The air "presses back," responding to the downward force of the wing with an opposed and equal force. This, as a side note, is how flat-winged paper airplanes generate enough lift to stay aloft longer than the same sheet of paper folded to a narrower shape.

So let's have three cheers for Newton for helping us understand how airplanes fly.