"FLAV8R" wrote in message
...
That would depend on what has the greater resistance,
the air in front of the plane or the belt on the treadmill.

No, it would not depend on that at all. Both of those effects are creating
a resistance in the same direction, and thus are additive. Which one is
greater is irrelevant. The only relevant question is whether they combined
exceed the thrust from the engines.

They don't even come close to doing that, and so the engines can easily push
the airplane forward to a high enough speed for flight.

[...]
You can equate it to an airboat in a river.
Will the river push the airboat down stream or
will the propulsion of the engine move it forward?

It's similar, yes. Except that the drag due to friction from the treadmill
is miniscule, whereas hydrodynamic drag is significant.

Pete