Under what circumstance can a batter hit the ball legally while one foot is airborne outside the batter's box?

A batter can legally hit the ball while one foot is airborne outside the batter's box if that airborne foot lands in the box immediately after making contact with the ball. This rule allows a player to maintain balance and a proper follow-through during the swing, as long as the foot that was outside the box returns to a legal position within the bounds immediately after the hit.

The rule aims to ensure that the batter is not deemed to have violated the batter's box rule while still allowing some flexibility in the batter's movements. Therefore, as long as the airborne foot lands within the box at the time of making contact with the ball and the batter does not interfere with the pitch, this action is considered legal. This is important for maintaining fairness and a precise playing environment in the game.