Heathrow brought in 5.8m passengers in January, marking a fresh high for the airport and its 15th consecutive record month.
Passenger volumes rose 1.1 per cent on 2017, with the London airport saying domestic flights were a key driver of growth. UK flights were up 6.9 per cent in the first month of 2018, following the increased uptake of Flybe's flights at the airport.
The airline launched new routes between the London airport and Edinburgh and Aberdeen in March last year.
Growth to South Asia and Latin America rose by 11.3 per cent and 6.9 per cent respectively.
Heathrow chief executive John Holland-Kaye said: "Heathrow is off to a flying start, with record passenger numbers and cargo volumes and the start of our public consultation on the third runway. Heathrow expansion will provide the global trading routes to super-charge Britain’s economy as we leave the EU.”
Growth in passenger numbers at the airport comes as Heathrow waits to expand with the development of its third runway. It launched a consultation last month into its cost-cutting proposals which it says could trim £2.5bn off the total cost, bringing that down to £14bn.
An inquiry into the government's national policy statement on Heathrow expansion is also underway by MPs on the Transport Select Committee, with transport secretary Chris Grayling facing questions last week.
Transport for London (TfL) meanwhile, has raised concerns over the impact that Heathrow expansion will have on the capital's transport network, warning over significant crowding.
The airport however, says its plans to "significantly improve" rail, bus and coach connections will enable "tens of millions" of extra journeys by passengers to be by public transport when heading to the airport.