Gatwick Airport has announced that all outbound flights are grounded until Tuesday morning due to the severe weather conditions.
It tweeted: "Sorry. No outbound flights from Gatwick until 6am Tuesday 21st December because of heavy snow."
Earlier, flights at Gatwick had begun to return to normal and about 400 services took off or landed.
Inbound flights may resume, depending on whether the runway can be cleared and de-iced, after more snow fell.
All passengers have been advised to check the flight status on their airline's website before setting off.