Staff at Gatwick Airport had to write information about flight departures on whiteboards because after a technical issue screens failed, affecting both the North and South terminals at the airport.
Photos posted on social media showed people crowding around the boards to find out the latest on their flights.
Staff could also be seen rubbing out information as it changed to update it with black and red marker pens.
Gatwick Airport tweeted: "We are sorry, but due to a Vodaphone IT issue our flight information is not displaying correctly. Please use the temporary flight boards in the departure lounges or listen for airline flight announcements. We are expecting to resolve the issue soon and apologise for the inconvenience."
There was frustration among some passengers who described walking to wrong gates or having their flights delayed.
A Gatwick spokesperson said a "handful of people had missed their flights" as a result of the problem.
A user by the name of @helenwalsh tweeted: "Absolute carnage @Gatwick_Airport with no boards working and no staff with gate info."
@robfahey posted a photo of people waiting by a whiteboard and wrote: "This tiny whiteboard is the only departures information in Gatwick Airport right now; every screen is offline. Utter chaos. This is a signature flourish at the end of a short trip that's been full of reminders of how badly the UK's infrastructure is crumbling."
Other passengers praised the efforts of staff members for trying to keep the flight schedule on track.
