Snow forced the closure of runways at Manchester and Liverpool Airports this morning.
One runway at Manchester re-opened at around 11.30am but the airport is still dealing with a backlog.
A spokeswoman for Manchester Airport said: "Our airfield team has been working through the night to keep the runways clear, which resulted in the day’s operations starting as planned. However, as conditions worsened significantly this morning, we took the decision to temporarily close our runways.
"We advise all customers to carefully plan their journey to and from the airport, as the surrounding road network is severely impacted, making it difficult to get onto the airport site. We are working closely with GMP and Highways England to monitor the situation. As we gradually increase operations we will take this into account to maximise the number of people able to make their flights.
"We appreciate the inconvenience caused to passengers, but their safety and security is always of paramount importance.
"We will continue to monitor the adverse weather throughout the day and will provide updates as required. Passengers are advised to check the status of their flight with their airline."
At Liverpool the runway was closed until 10.30. Flights have now resumed but the airport warned that flights are still being delayed. It told passengers to contact their airline direct for information.
Yellow warnings for snow and ice warnings are in place for most of the UK.
Heathrow Airport told passengers to drive safely to the airport in the wintry weather.