Three days later, check-in services failed at the terminal, with 50 flights delayed. Cyberattacks could have "an effect analogous with the recent Icelandic volcanic ash problems, shutting down air travel across parts of Europe for several days. In that case estimated costs run into the billions of dollars or euros," the ICAO wrote.
ICAO's 12th Air Navigation Conference is scheduled to run from Nov. 19-30 in Montreal.
Send news tips and comments to email@example.com. Follow me on Twitter: @jeremy_kirk