Forty flights out of Heathrow had been cancelled before 9am after the severe weather reduced visibility in South East England with fog also hampering early morning flights in the Midlands.
Weather conditions had a knock-on effect at Glasgow Airport where a BA flight to London City and another to Heathrow were scrapped with the airline also cancelling two flights from London to Scotland's biggest city.
Passengers at Glasgow also faced a three-hour delay before their flybe flight to the East Midlands took off as a result of the fog.
A spokesman at Glasgow Airport said: "If conditions continue then the situation could get a lot worse."
Lara Gunn, a weather forecaster at the MeteoGroup warned: "A dense fog is hanging over the South East and up towards the Midlands and is expected to linger throughout the morning. Visibility will be quite poor in some areas and so travellers should take caution."
Passengers are urged to speak to their airline in advance.
Today's flight problems follow last Saturday's major disruption at all airports after difficulties at the Hampshire headquarters of air traffic control company Nats.
Then yesterday an accident involving a landing aircraft at Stansted meant no planes were able to land at the Essex airport for around three hours.