The UK's Gatwick and Heathrow airports have released their annual passenger traffic figures for 2014, with the former recording its busiest year with 38.1 million passengers.
Gatwick posted an increase of 7.6% in 2014, with December servicing 2.5 million passengers, an 8% more than the previous year.
Heathrow recorded 73.4 million passengers, an increase of 1.4% from 2013. It was the busiest ever December at the airport with 5.93 million passengers.
The two airports attributed the growth in passenger traffic to long-haul services.
The launch of low-cost long haul flights to New York and Los Angeles helped Gatwick drive a 2.8% growth in flights to North America, while traffic to other long haul destinations saw an increase of 12.1%.
"Only by expanding Heathrow can we add direct flights to the world's growing cities, increase our exports and connect all of the UK to global growth."
Passenger volumes of Heathrow continued growth within emerging markets, increasing 15.1% to China, 10.9% to Mexico and 4% to the Middle East and Central Asia, the airport said.
London Gatwick chief financial officer Nick Dunn said: "Gatwick's record-breaking figures show an airport serving the widest range of travel and airline models, exactly what is needed from the decision about the UK's next runway.
"Airport expansion should be for the many not the few, and our broad range of growth underlines that Gatwick is the obvious solution if we want all passengers and all types of travel to benefit.
"Expand Heathrow and we take a backwards step towards higher fares, less choice and the monopolies of the past. Only Gatwick can offer the win-win solution of a bigger Gatwick, a better Heathrow and airports throughout the UK benefitting from greater competition."
Heathrow CEO John Holland-Kaye said: "Vietnam Airlines' announcement that it is moving its operation from Gatwick to Heathrow is good news for the UK as it secures a direct flight to an important growth economy, with more frequent flights and cargo capacity.
"It also underlines that airlines can only make flights to many long-haul destinations viable from a hub airport like Heathrow.
Gatwick and Heathrow are in the race for a new runway. Gatwick has currently one runway whereas Heathrow has two.
Gatwick has submitted a proposal to the Airports Commission in 2013 to build a second runway with an investment of up to £9bn. Heathrow is lobbying for a third runway.