Why were we afraid of heights?
When Harry first mounted a broomstick, he was soon able to fly a short distance and catch the Remembrall Malfoy had thrown. This caught Minerva McGonagall's attention, and he was subsequently admitted to Gryffindor's Quidditch team.
When Harry first rode on Buckbeak's back, he also circled the school without any trouble or mishap.
Whether it was a broomstick or Buckbeak, Harry, who came from the Muggle world, had never encountered either before. Yet it seemed that whenever flying was involved, he learned without needing a teacher.
Except during the third-year Quidditch match between Gryffindor and Hufflepuff. That day brought not only thunder and lightning, but also Dementors. Harry fell from his broom, and if not for Dumbledore's slowing charm and the Phoenix Patronus, no one could have predicted what might have happened.
Creatures died when they fell from great heights. That was considered "common sense," so Pomona felt no explanation was needed for why Lockhart used "alarte ascendare" on the venomous snake Draco Malfoy had summoned during Dueling Club, hurling it high into the air.
In nature, eagles could also be seen gripping snakes and carrying them high into the sky. Unfortunately, that venomous snake did not "die" as Lockhart had expected.
Was it because it had not "flown" high enough? Or was there another reason—that snake, which looked so much like a living creature, was not alive at all, but a quasi-lifeform like a transfigured frog-rabbit? It had never truly lived, so there was no question of "death."
"If you dueled Patricia Linnaeus, what odds do you think you would have?" Pomona had once asked after the first demonstration at Dueling Club.
Snape had first looked at her in surprise, then laughed as though he had heard something amusing, revealing his yellowed teeth.