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if the runway had an enormous fan blowing from behind- the plane could still move forward, and would do so with greater ease, but the wings could not create lift.

Correct.

Quote:
the rolling belt under the plane would still have little or no effect.

Well, little effect. Rolling resistance is a factor. If I'm understanding the way the question was posed, the plane would actually take off easier because the belt would eliminate rolling resistance.
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Tony Fabris