Li recounted the challenges: heavy clouds, thunderstorms with turbulence severe enough to damage aircraft, sand and dust that could lower ground visibility to zero, and a lack of oxygen for ground staff.

"In the 1990s, there were sandstorms every afternoon in Lhasa. We had to plant thousands of trees around the airport to keep the air clean," said Li, who headed the bureau during the period.

The first flight from Beijing to Lhasa was made by an Il-18 aircraft on March 1, 1965.

"Over the decades, people working in aviation in Tibet have made great contributions and sacrifices to ensure the industry's safety and development," said Li, adding that better navigation technology also improved safety.

Aviation helped Nyingchi, in eastern Tibet, earn 1.11 billion yuan ($177 million) in tourist revenue last year. The figure jumped 11 times compared to the number ten years ago.

"Tibet's tourism, express delivery and other industries wouldn't have flourished if it were not for the air connections," said Li Hancheng, the current director of the Tibetan aviation bureau.

GROWTH BRINGS CHALLENGES

According to a national plan for Tibet's development, in the next five years, the number of flights between Tibet and other cities will increase to 95. Annual passenger volume will reach 6.6 million by 2020.

Officials told Xinhua that passenger volume has reached twice the designed capacity at Konggar and Nyingchi airports.

"The infrastructure is in urgent need of further expansion and upgrades," Li said.

"Brain drain" is also a challenge. Dissatisfied with harsh work conditions, some pilots and airport staff have chosen to work elsewhere.

"It takes at least eight years to train a seasoned captain, because we have stricter requirements for flying the Tibetan route. We need to recruit experienced pilots to expand business," said Bai Weisan, vice manager of Tibet Airlines.

"We will improve wages for staff to keep them working here," he said.