Imagine Pegasus ponies using tandem skydiving harnesses to get airborne Earth ponies and Unicorn ponies whose magic is not strong enough to use a levitation spell to fly. That method of flying is far safer than holding someone else in your forelegs. Tandem skydiving harnesses can be used for Earth ponies and Unicorn ponies to travel on business or pleasure, or for the thrill of flying. In the military, tandem skydiving harnesses can be used as a way to silently get Earth and Unicorn ponies into places undetected by any hostile forces.

Provided you can find pegasi who could LIFT an earth pony or unicorn. Griffons would be a better idea.

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Fluttershy can lift a unicorn. Shouldn't be too hard.

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To quote Dick Martin, "I didn't know that..."

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Having Pegasus ponies using tandem skydiving harnesses to get wingless ponies and other creatures to become airborne is one way to expand the narrative possibilities in our stories. The best fan fiction creates original scenarios, characters, and objects, based upon real-world scenarios, characters, and objects, which in turn creative more entertaining stories than the source franchise or franchises.