Christmas and New Year reunions fuelled passenger growth at Heathrow last month.
The London hub handled more than 6.7 million passengers over the festive season.
Numbers rose by 3.1% over the same month last year – the strongest monthly increase recorded for 2019 – to make it the airport’s busiest December ever.
The monthly performance contributed to a record 80.9 million passengers using the airport in 2019, with growth driven by larger and fuller aircraft.
The biggest surge in December traffic came from a 10.6% rise in domestic passengers, including those travelling on Flybe routes to Newquay and Guernsey during the holiday rush.
British Airways also increased the frequency and aircraft size of its Scottish services to coincide with Hogmanay celebrations.
The Middle East saw growth of 7.3%, likely boosted by fans flying out to Qatar to watch Liverpool win the FIFA Club World Cup.
This was followed by the US, up 7.1%, helped by new flights to Pittsburgh, Las Vegas and Salt Lake City.
Heathrow chief executive John Holland-Kaye said: “The past decade has been transformational for Heathrow and the investments that we’ve made in our infrastructure, our people and our processes are paying off for passengers.
“But it doesn’t end there. By the end of this new decade of delivery, a third runway will have given Britain more hub capacity than our rivals in France or Germany, making this country a winner and the best-connected country in the world.
“Regular, direct flights to all the major cities in the US, India and China – the great economies of the 21st century – will put all of Britain at the heart of global trade and we look forward to delivering this economic growth in a way that aligns with the committee on climate change’s net zero 2050 target.”