In flight

In baseball, the rules state that a batted ball is considered in flight when it has not yet touched any object other than a fielder or his equipment.

Once a batted ball touches the ground, a fence or wall, a foul pole, a base, the pitcher's rubber, an umpire, or a baserunner, it is no longer in flight. A batted ball that passes entirely out of the playing field ceases to be in flight when that occurs.