A “system wide” computer bug has caused travel chaos for thousands of Delta passengers.

The US airline took to Twitter to tell passengers: “Our systems are down everywhere,” with delays being reported at airports in the US, the UK, Iceland, and Japan.

Flights that are en-route are unaffected, but passengers that are waiting to board have been told to check their flight status while the issue is being addressed.

The computer outage has resulted in many passengers being stranded at airports around the world due to problems checking into and boarding Delta flights.

The second largest airline in the world, it had almost 140 million passengers travelling with it in 2015.

Delta said in a statement: “Delta experienced a computer outage that has impacted flights scheduled for this morning.

“Flights awaiting departure are currently delayed. Flights en-route are operating normally.”

Delta isn’t the first airline to have been hit by a software problem with American Airlines forced to delay dozens of flights in April 2015 due to a glitch on their iPads.

The problem resulted in many pilots being unable to access in-flight information. The issue was related to an app which the pilots use as an “electronic flight bag” that was introduced as a replacement for paper manuals.

Currently all flights with Delta awaiting departure have been delayed.

With the school year restarting in just a few weeks time August typically presents many with a final opportunity to get away before the end of the summer.

Many passengers took to Twitter to vent their frustrations.Delta Twitter passenger