Heathrow chief executive John Holland-Kaye has pledged to keep passenger charges flat even if the airport is granted permission to build a third runway.
The government will formally decide next week between Heathrow and Gatwick which airport should be given the green light to expand, but some airlines have voiced concerns over the impact of expanding the former.
In June, Willie Walsh, chief executive of International Airlines Group (IAG), the owner of British Airways and Heathrow's biggest customer, accused Britain's largest airport of "ripping off" passengers amid new runway plans, which he said could cost about £16.5bn ($20.2bn).
Walsh said such a move would result in passengers paying £80 towards landing charges per return trip, which is double the present charge of £40.
However, Holland-Kaye said the airport could afford a third runway without hiking per-passenger charges.
"Through the planning and build period, we can keep prices flat on average compared to today," he was quoted as saying by the Financial Times. "What that means is that there will be some years where they are going down, some where they are going up. That is a very good position to be in."
Per-passenger charges have been steadily declining over the past few years and are forecast to account for 68% of the airport's income from air operations next year.
However, Holland-Kaye's words did not impress IAG and the company said the average was calculated over a period stretching up to 30 years.
"Their figures cannot deliver their stated aim of making Heathrow and the UK competitive," said the owner of British Airways and Aer Lingus.
Walsh has not been the only executive to be vocal about the impact of Heathrow's proposed expansion. Last week, Alex Cruz, chief executive of British Airways, urged the airport's shareholders to finance the construction from their own funds, rather than by increasing charges to passengers and airlines.
On Thursday (20 October), the airport reported a rise in profits for the first nine months of 2016 and claimed increased support for its plans to build a third runway.
The airport saw a 0.7% annual increase in the number of passengers passing through to a record high 57.3 million in the January to September period. Pre-tax profits climbed 11% to £202m, while revenue rose 1.2% to £2.09bn.