Monthly passenger numbers at Heathrow fell below 500,000 last month, the lowest since 1966.
The airport said the decline was due to the ban on all but essential travel, blanket quarantine, pre-departure and post-arrival testing.
In total, just 461,000 passengers made a trip from Heathrow, down 91 per cent from last year.
Limits on passenger flights, which normally carry freight, mean cargo volumes also remain 30 per cent down on an annual basis.
However, EU rivals including Frankfurt, Paris Charles de Gaulle and Schiphol airports have now all returned to pre-Covid cargo tonnage levels.
Heathrow chief executive, John Holland-Kaye, said: “Aviation has always led the UK economy out of recession, and we will do so again.
“The global travel taskforce can lead the way on reopening international travel and trade safely – but ministers must get a grip of Border Force’s performance so that visitors get a warm welcome to Britain, not a six-hour queue.”
Huge queues have been reported at Heathrow in recent days as border agents struggle to meet Covid-19 restrictions on work practices and efficiently process passengers.
The global taskforce is expected to report on the reopening of travel on April 12th.