Traveling by road is the most popular way of transportation in Tibet. There are railways and airports (five) but due to geographical limitations, it might not be your best option. Although there are many regions still not reachable, almost every significant town or city is connected with well-constructed roads here. Multiple trans-boundary highways connect Tibet to Nepal, India, and Pakistan. For long-distance travel, airports are better while buses and vans are available for a short distance within Tibet. Entering Tibet is easiest by air landing at Lhasa Gonggar Airport.
If you are here from mainland China, Train and Buses might be a good and scenic alternative as well. Similarly, for multi-country overland trips to Tibet, it is recommended to be done in nice weather due to elevation and geography here.