BA said all short-haul flights out of Heathrow were cancelled but it aimed to run as many long-haul ones as possible.
Gatwick, Stansted, Edinburgh and Birmingham airports are open. Meanwhile, the Met Office has warned of more snow and ice in many parts of the country. A Gatwick spokeswoman said it was doing everything it could to "get passengers on their way" but advised them to check with airlines before setting out. Luton, Exeter, London City, Birmingham, Bristol and Southampton airports said flights would be subject to delays and cancellations.
Exeter has closed a runway until at least 1900 GMT. Flybe has cancelled all departures from there on Monday. Stansted is said to be operating as normal.