How can I maintain my baby's sleep routine while we are traveling?

Keep schedule. In early infancy sleeping is wraped around a schedule of feeding and body maintaince. As much as possible, to keep baby on their baseline feeding schedule and the rest should fall into place. Infant carriers & strolers with covers can help you create a calm zone almost anywhere. Direct flights are the best choice. Feeding while landing often reduces crying episodes.
Sleeping patterns. In part depends on the type of travel that you will be doing. If flying, as soon as you can after take off, offer your baby a drink. This will help to ease the pressure in their ears, as well as preventing dehydration. Allow your baby to sleep as much as they like on the plane. Feed at the usual times, and let your baby familiarize with the new environment. Try to travel at night.