Since 20 September 2017, industrial action at Avianca Airlines, Colombia’s largest airline, has caused significant delays and cancellations for Avianca passengers. Domestic flights have been most affected, but some international Avianca flights to and from Colombia have also been cancelled. You may experience disruption to air travel. Contact your airline or travel agent before you travel. The level of our advice has not changed. Exercise a high degree of caution in Colombia. Higher levels apply in some parts of the country.
Source: Smart traveller