By air
There is normally one direct flight a day from Shanghai to Lhasa, leaving early in the morning and arriving in the afternoon, about eight hours including the stop. Booking early helps with fares in peak season.
By train
Train Z164 leaves Shanghai in the evening and arrives in Lhasa in the evening of the third day, about 47 hours, with a hard sleeper around 1,260 yuan.
A useful combination
Fly to Xining and take the train from there: the Xining–Lhasa section is the most scenic part of the Qinghai-Tibet line, and the shorter rail leg is easier on the body than two full days on the train.
Documents
Foreign travellers need the Tibet Travel Permit arranged ahead of time; bring the passport used for the application and keep it with you on the train and at checkpoints.