For the benefit of the rest of the board, Gary believes in a geostatic universe, where the Earth is not rotating.
Quite correct, Rob.
Gary, what
exactly is your assertion about east/west travel with an aircraft? Are you saying that aircraft can't fly in a moving atmosphere? Or that aircraft don't get their lift from the atmosphere?
The assertion, Rob, is not the fact that the airplane's jet engines propel the plane forward in a relative motion to the earth. That much is agreed upon. The problem comes in with the "original motion" of the plane. You have a belief that a still plane on the ground is travelling as fast as the earth spins (which makes sense in an acentric view), and that as soon as it leaves the ground it will still somehow retain this "original motion" component of its velocity. This is much the same as the rocket flying to the 1st quarter moon issue we hashed out.
There, you were correct because there is nothing in the vacuum of space to drag on the speed of the rocket as it hurls through space (this purely avoiding the aether issue for this argument), and occasionally thrusts here and there to adjust its speed relative both the earth and moon. In other words, the rocket always maintains the "original motion" that it had when it was on the earth, ie., 66,000 mph. We are fine to this point, and agree.
Now, however, does the airplane do the same thing as the rocket ship? When it leaves the ground, does its "original motion" from the spinning earth remain as a constant the entire time it is in the air? My point to you is two-fold. First, there is the question of "drive". Second is the question of "drag".
What "drives" or "powers" or "carries along" the airplane at its original motion speed? With the rocket there was nothing. It just automatically retained what was given to it when it left the earth. There was nothing out in space to slow it down and therefore no extra force was especially needed to maintain this part of the rocket's motion.
But here's the rub. In the atmosphere of earth, the plane does not have a resistance-free environment. Once the plane has left the ground, both the plane's "original motion" and "relative motion" meet immediate resistance. Besides gravity pulling downward, the air resists motion through it. So, therefore, if the jet's engines are carrying the plane forward at 500 mph relative to the earth, what is the "engine" working to maintain the "original motion" that the plane took off with?
Is this clear?

Originally Posted by
Gary Shelton
But what keeps the airplane's "original motion" going?
The thrust from the jet engines or the turboprops? I think you need to define 'original motion' for us here.
The engines of the plane work only to move the plane along "relative" (gosh am I using your word too much?) to the ground. The "original motion" of an object is the speed that thing had when it left contact with a second object it is riding upon.

Originally Posted by
Gary Shelton
the air, well, it cannot have any ability to "push" or "carry" the plane because it is a gas
Have you ever made a paper airplane? What holds it up?
Rob