Heathrow handled 37 million passengers in the first half of the year, including some of the busiest days on record, but still remains in the red.
Overall passenger numbers still remain “consistently below” pre-pandemic levels, with the cost of living crisis “a material headwind” for second-half demand.
Adjusted pre-tax losses for the period to June 30 more than halved year-on-year to £139 million from £321 million.
Heathrow complained that it remained loss-making due to the Civil Aviation Authority setting “too low” a revenue allowance in the latest regulatory settlement for the next five years to generate enough cashflow, a decision which is now subject to an appeal to the Competition and Markets Authority (CMA).
The airport said: “While we await the outcome of the CMA appeal, we are preparing to kick off the next phase of our investment in Heathrow to improve service.
“Plans for up to £3.7 billion of passenger improvements will include the replacement of the Terminal 2 baggage system and streamlining security in all terminals.”
Looking forward, Heathrow added: “We are giving great passenger service, with almost all passengers waiting less than five minutes at security as the summer peak gets underway.
“We have also now agreed on a fair two-year pay deal for all frontline colleagues.”
The airport’s network this summer serves more than 225 destinations, including 12 routes to UK airports after domestic airlines charges were trimmed.
Heathrow is offering 248 daily flights to 31 US destinations and claimed to be better connected to India and China than other European hubs.
British Airways has launched a new route to Cincinnati, JetBlue added another service to New York, and South American carrier Latam has been allocated slots to start a new non-stop connection to Lima in Peru.
Chief executive John Holland-Kaye, whims stepping down in October, said: “The summer getaway has got off to a great start, thanks to planning and close collaboration with airlines and their ground handlers.
“I am immensely proud of what we have achieved as a team in the last nine years, transforming Heathrow into a world-class airport that Britain can be proud of.
“Heathrow is now a leader in sustainability, with a diverse culture that reflects our local community and can attract the best talent from around the world.”