The Times has reported that Department for Transport deputy director of aviation Sarah Bishop has said the current estimates for passenger numbers made three years ago already look out of date.
Instead, she said demand at the national level was already growing 10% quicker, meaning an additional runway would be a temporary solution at best.
Speaking at a recent meeting of the Wetsminster energy, environment and transport forum she said by 2050: "we are expecting that there will be capacity constraints once more, even with a third runway at Heathrow.
"Capacity in the southeast up to 2030 will be well served with an additional runway at Heathrow, but there may be a need for a runway beyond that looking out to 2050."
A total of 285 million people flew in and out of the UK last year, a 5.6% increase on the 270 million the previous year.