On Wednesday, Europe's busiest hub reported pretax profit of $47.91 million.
That was well up from a loss of $863.7 million a year before.
Heathrow said the popularity of transatlantic travel, particularly to New York pushed passenger numbers to 79.2 million.
Overall, passenger numbers were close to pre-health crisis levels.
The airport also expects to add another 2 million travelers this year.
Surging demand will boost the airport's finances.
But it also faces a 20% cut in real terms to its charges this year under new prices set by regulators.
The return to profit also comes as a number of Heathrow's current shareholders try to sell their stakes in the airport.
Last year, Spain's Ferrovial agreed to sell its 25% holding in Heathrow for $3 billion to Saudi Arabia's Public Investment Fund and Ardian.