" When you’re flying, the changing balance of lift and weight pulls you up or down. But another pair of forces pulls you forward or backward through the air: thrust and drag. Thrust is the power that pulls the kite forward—you run with it to get it up in the air. You have to have thrust to create lift. Drag is there because your kite’s surfaces push against the air and slow the kite down. Drag doesn’t pull you out of the sky; it makes you fly more slowly. "

― Elizabeth Wein , Rose Under Fire