Instructions
Log in to the game with your "World of Warcraft" character. Press "Enter," then type "/bartender" without quotations. Press "Enter again." The Bartender 4 options window will appear.
Click "Pet Bar" from the left pane. Click the "Visibility" tab at the top of the window.
Click one of the check boxes to hide the pet bar automatically. For example, click the "Hide with vehicle UI" check box to hide the pet bar automatically when in a vehicle. Click the red "Close" button at the bottom right of the window.