https://www.bloomberg.com/news/articles/2017-08-25/brexit-bulletin-when-silence-isn-t-golden
http://openeurope.org.uk/today/blog/will-brexit-ground-flights-europe/
http://blogs.lse.ac.uk/brexit/2017/12/05/a-high-risk-game-of-chicken-is-being-played-over-the-irish-border/