“We don’t understand how interconnected we are until you can’t do it anymore,” he said.

About 17,000 flights were canceled Saturday, and travelers scrambled to find accommodation or land routes home during what is already the worst disruption in international air travel since the attacks of Sept. 11, 2001, when all air travel in and out of the United States was halted for three days...“We don’t understand how interconnected we are until you can’t do it anymore,” he said."

NYTimes: "Air Travel Crisis Deepens as Europe Fears Wider Impact"