Interesting topic.
Back in 1996 I was involved with teaching Aviation English at the China Southern Airlines Flying College at the Beijing University of Aeronautics and Astronautics in Beijing. I found it to be "interesting," to say the least. There was a BIG need for English language instruction, the cheaper (or better yet free) they could get it, the better. There is the need, the money and resources may not be at the same level as their interest and need.
PM me if you need more info.