Some facts about flying
HAVE YOU EVER watched a balloon as it slowly meandered upward into the sky? The balloon is able to fly because the air within it is lighter than the surrounding air—just set it free and it’s off. Many people think quite differently about airplanes, however. Knowing that these machines are clearly heavier than air, they might wonder what exactly keeps an airplane in the sky. And they might fear that any airplane might just fall out of the sky.