There are no direct long-haul flights to Tibet. You will almost certainly have to stop for at least a night in Chengdu, Guangzhou or Beijing, as you need to to pick up your permit or meet your group in your chosen gateway city before heading to Lhasa.
If routing via Kathmandu, you'll have to budget at least four working days there in order to secure your Chinese group visa.
For China, you generally have the choice of flying first to Beijing (http://en.bcia.com.cn), Shanghai (www.shanghai-airport.com), Guangzhou (www.guangzhouairportonline.com) or Hong Kong (www.hongkongairport.com); there is also a small but growing number of international flights direct to Chengdu (www.cdairport.com/en). There’s little difference in fares to these airports,
There are direct flights from Beijing and Shanghai to Lhasa, so it is no longer necessary to first fly into Chengdu.
Generally speaking, long-haul flights to/from Kathmandu are relatively expensive, as a limited number of carriers operate out of the Nepali capital. The national carrier, Nepal Airlines (www.nepalairlines.com.np), is notoriously unreliable and is to be avoided if possible.
One option is to buy separate discounted flights to Delhi and from Delhi on to Kathmandu, but note that without a single through ticket you will likely have to arrange an Indian transit or tourist visa in order to pick up your baggage and transfer between flights at Delhi airport.
International airlines flying into and out of Kathmandu include the following.
Air India (www.airindia.in) Good connections via New Delhi.
China Southern (www.csair.com/en/) Good option from Australia via Guangzhou.
Etihad (www.etihad.com) Quality airline with fast connections through the Middle East, but pricier than most.
Jet Airways (www.jetairways.com) Good service and connections via New Delhi.
Thai Airways (www.thaiairways.com) Popular flights from Bangkok.
Turkish Airlines (www.turkishairlines.com) Fast connections from Europe via Istanbul.
Chengdu's Shuangliu International Airport is well connected to other cities in China, with daily flights arriving from Beijing, Shanghai, Guangzhou, Kunming and Hong Kong among others. There is also a growing number of international carriers making nonstop flights into Chengdu, mainly from Asian hubs like Bangkok, Kuala Lumpur, Seoul, Tokyo and Singapore. From Europe it’s possible to reach Chengdu nonstop from Amsterdam and Frankfurt, and from the USA there are direct flights from Los Angeles and San Francisco. Arriving from other international destinations will likely require you to change planes and possibly make a layover in a mainland Chinese hub.
International airlines flying into Chengdu include the following.
Air Asia (www.airasia.com) From Kuala Lumpur.
Air China (www.airchina.com) From Frankfurt, Hong Kong, Bangkok, Kathmandu, Paris, Rome, Singapore, Sydney, Seoul and Tokyo.
Asiana (www.flyasiana.com) From Seoul.
China Eastern (http://ph.ceair.com/en/) From Bangkok and Osaka.
China Southern (www.csair.com/en/) From Amsterdam and many cities via Guangzhou.
Etihad (www.etihad.com) Via Abu Dhabi.
Hainan Airlines (www.hainanairlines.com) From Los Angeles and New York
KLM (www.klm.com) From Amsterdam.
Qatar Airways (www.qatarairways.com) Via Doha.
Sichuan Airlines (https://global.sichuanair.com/US-EN) From Auckland, Bangkok, Chiang Rai, Kathmandu, Melbourne, Seoul, Singapore, Tokyo and Vancouver.
United Airlines (www.united.com) From San Francisco.
Departure tax in China is worked into the price of both domestic and international tickets, so there’s nothing additional to pay at the airport.
There are essentially two ways to buy an air ticket to Tibet's gateway cities: buy a single international ticket to a city like Chengdu or buy an international ticket to Beijing, Shanghai or Guangzhou and then buy a discounted domestic Chinese air ticket online.
Note that if transiting through a city like Beijing en route to a domestic Chinese destination you will need to clear immigration and customs in Beijing, so allow plenty of time for your domestic connection.
You can buy discounted domestic tickets within China (except Lhasa) from online Chinese ticket agencies such as Elong (www.elong.net) and Trip (www.trip.com). These sites can sell you tickets to gateway cities but will not sell you a ticket from Chengdu to Tibet without Chinese ID, though international online ticket sites such as One Travel (www.onetravel.com) and Expedia (www.expedia.com) will. If this all sounds too complicated, you can always ask your Tibetan tour agency to handle domestic tickets to Lhasa.
Airfares to China peak between June and September.
Within China there are flight connections to Lhasa from a dozen cities (and growing), including direct flights from Beijing, Guangzhou, Lanzhou, Xi'an, Xining and Kunming.
There are also some interesting daily flights within the Tibetan world, namely from Lhasa to Yushu (Jyekundo; ¥1060) in Qinghai, Xiahe (¥1950) in Gansu, Kangding (¥1500) in Sichuan and Deqin (also known as Zhongdian, Gyeltang or Shangri-la) in Yunnan. Some of the more obscure routes are with the Chinese budget airline Lucky Air (Xiángpéng Hángkōng; www.luckyair.net).
That said, most travellers still fly in to Lhasa from Chengdu, as there are more flights, cheaper fares and more tour agencies there. There are also flights from Chengdu to Nyingtri (Línzhī).
Your Tibet permit will be checked when checking in for your flight to Lhasa, as well as on arrival at Lhasa’s Gongkar airport.
Note that flights to and from Lhasa are sometimes cancelled or delayed in the winter months, so if you are flying at this time give yourself a couple of days’ leeway if you have a connecting flight.
Baggage allowance on flights to Lhasa is 20kg in economy class and 40kg in 1st class, so you’ll have to limit your gear to avoid penalties, regardless of what you are allowed to bring on your international flight into China.
Air China and Sichuan Airlines operate flights between Kathmandu and Lhasa daily in high season. Fares vary wildly between US$200 and US$400 one way, depending on the month.
Individual travellers can’t buy air tickets from the Air China office in Kathmandu without a TTB permit, but it doesn't seem a problem to buy them online. To board the plane you'll have to show your group China visa, which you'll only get through booking a tour with a Lhasa- or Kathmandu-based agency.
It is possible to buy air tickets from Kathmandu to other destinations in China, such as Chengdu (from US$280 one way); you don’t need a Tibet Tourism Bureau (TTB) permit to take these flights.
Chengdu has long been the main gateway to Lhasa for travellers coming by air, and multiple flights a day go to Lhasa in the height of summer. Flights cost ¥1680 one way but are often discounted down to ¥1200.
Flights into Lhasa are operated by Air China (CA; www.airchina.com.cn), Sichuan Airlines (3U; www.scal.com.cn), Tibet Airlines (TV; wwwtibetairlines.com) and China Eastern (MU; http://ph.ceair.com/en/, www.ceair.com). Note that on many online booking sites you need to spell Lhasa as 'Lasa'.
Try to book the first flight of the day because weather conditions and visibility will be optimal in the morning. On a clear day the views from the plane are stupendous, so try to get a window seat. In general the best views are from the left side of the plane from Chengdu to Lhasa and the right side from Lhasa to Chengdu. Getting into Lhasa early also gives you a little more time to acclimatise if you are on a short tour.
If you are coming to Tibet from somewhere outside China, have your agency mail your permit to a hotel in Chengdu, where you can pick it up and fly out the next day. Make sure the permit is sent a few days before you arrive and preferably let the hotel know it's coming.
There are also daily flights (¥1530) from Chengdu to Nyingtri (Nyingchi; Línzhī) in eastern Tibet, which might be an offbeat option if you plan to visit the Kongpo region. At around 3000m elevation, the region is lower than Lhasa and so helps with acclimatisation.
There are some useful daily flight connections between Lhasa and the popular traveller centres of Lijiang, Kunming and Deqin (the main airport for Zhongdian, also known as Gyeltang or Shangri-la). As with other flights to Lhasa, foreigners won’t be allowed on board without a TTB permit.