Where is the highest airstip in the world?

2 answers

La Paz Bolivia
Here is another answer: Bangda, China (elevation 4334 m). It is located between Chengdu and Lhasa.
http://www.boeing.com/news/releases/1995/news.release.950501.html
Ladakh, Pakistan is "only" at 3256 m, and Lhasa, Tibet (where I was earlier last year) is at 3650 m. They all have commercial airports. La Paz, Bolivia has an airport at 4040 m elevation.