Tibet Tourism Bureau Permit The official Tibetan government line is that a TTB permit is required to visit Tibet full stop. If you fly from Chengdu you will need to show this permit when you check in and one member of your group will probably carry the group TTB permit on the plane and hand it over to the guide at Lhasa. TTB permits are also needed by groups traveling by Land Cruiser but this will be arranged by the travel agency organizing the trip.