Long-haul routes helped boost a 12.1% rise in January passenger numbers to 2.8 million using Gatwick as the airport continued to push for expansion.
Rival Heathrow has won government backing for a third runway, but Gatwick believes it also represents an option for expanding airport capacity in the south-east.
Overall long-haul growth of 23.2% was recorded on the same time last year, with a 55.3% rise in transatlantic travel.
New York, Hong Kong, Costa Rica, San Francisco and Calgary were among the top long-haul destinations last month.
Airport CEO Stewart Wingate said: “Gatwick continues to set new precedents for a single-runway airport – we now serve 43.4 million passengers annually.
“With more than 20 new routes added to the airport’s destinations last year, driving long-haul growth of +23.2% in January, Gatwick continues to demonstrate the benefits of competition in the London airport market.
“Further new routes already confirmed to start this summer include Xi’an, China – the UK’s only direct route to the home of the terracotta army – plus British Airways providing passengers with more choice on routes to Oakland and Fort Lauderdale adding to Norwegian’s existing services to these destinations.
“Gatwick’s booming long-haul services and increased cargo volumes this January once again prove the vital role the airport plays in the UK economy at this crucial time for the country, as we continue to offer the UK government a credible and deliverable option for runway expansion.”
Iceland saw a 64% spike in numbers as it grew in strength as a winter holiday destination.
The top performing domestic routes included the Channel Islands, Belfast, Newquay, the Isle of Man and Inverness.