Can you get hemorrhoids from flying on a plane? Does the elevation have an effect on them or is just from sitting? A friend said she got a hemorrhoid from riding on a plane.

Airplane travel. By itself does not cause hemorrhoids. But air travel can cause severe dehydration, leading to constipation at conclusion of flight and thus straining and a flare of hemorrhoids. You lose 20 ounces of fluids per hour of air travel just sleeping on the plane. I recommend drinkingat least 20 ounces every hour of air travel and must be caffeine free/alcohol free fluids, to avoid constipation.
Hemorrhoids . Hemorrhoids can occur with heavy lifting and straining. They are very common. It seems that your friend's problem was probably a coincidence during an airplane flight.