air wall; sky wall 空牆

air wall; sky wall
繁：空牆
简：空墙

但本報發現，國家民航局早於2009年就解除珠三角「空牆」訂立的三部曲，表明要等香港民航處2013年新管制中心及系統建成啟用後，再商討協調珠三角空域安排，而有關空管系統卻因種種問題延至2016年才啟用，已較原定時間表延遲3年。

「拆空牆」三部曲 港空管問題延誤（2015年4月6日）。明報，取自 https://news.mingpao.com/pns/「拆空牆」三部曲%20港空管問題延誤-民航局曾表明%20空域安排須待新系統啟用/web_tc/article/20150406/s00002/1428255702348

Recently, during the consultation on the third runway project of Hong Kong international airport, some people said the “air wall” problem on the mainland might compromise the new runway.

HK and mainland vital to Asia’s future economic destiny. (2015, April 10). China Daily. Retrieved from http://www.chinadailyasia.com/opinion/2015-04/10/content_15249198.html

The government would say only that the “problems will no longer exist” in five years, as it remained tight-lipped about whether Hong Kong could eventually circumvent a “sky wall” imposed by the mainland between the city and the national airspace.

Kao, E., and Ng, J. (2015, March 18). Approval of third runway at Chek Lap Kok airport does not answer questions about airspace. South China Morning Post. Retrieved from http://www.scmp.com/news/hong-kong/article/1740549/approval-third-runway-chek-lap-kok-airport-does-not-answer-questions