Flyby Attack( Monster Compendium: Monsters of FaerÃ»n, p. 9)
The creature can attack on the wing.
When flying, the creature can take a move action (including a dive) and another partial action at any point during the move. The creature cannot take a second move action during a round when it makes a flyby attack.
Without this feat, the creature takes a partial action either before or after its move.