You are allowed to travel while your court case is pending. When you hire a lawyer to defend you of your pending DUI charge, they will probably inform you that you needn't attend the first few non-essential court dates, since a lawyer can attend those hearing for you. Remember that you will need some form of government I.D. to get through the airport, and keep in mind, that if your license is being held by the police, it may difficult to rent cars in other cities during your travels.