Heathrow Airport said it has suffered a 90,000 decline in passenger numbers on routes included in a £10 per person Government scheme.
It described the electronic travel authorisation (ETA) system as “devastating for our hub competitiveness”.
The Conservative government introduced ETAs in November 2023 for people entering or transiting through the UK without legal residence or a visa.
ETAs, which cost £10, are required for nationals of Qatar, Bahrain, Kuwait, Oman, the United Arab Emirates, Saudi Arabia and Jordan.
The programme is scheduled to be extended to the rest of the world this autumn, although for travellers from the European Union, the European Economic Area and Swiss nationals it will be introduced early next year.
Heathrow said in a statement: “While Heathrow continues to attract new routes and record passenger numbers, the latest data following the introduction of the ETA shows that Heathrow has lost 90,000 transfer passengers on routes operating to and from the seven countries included in the scheme, since its introduction in 2023.
“This is devastating for our hub competitiveness.
“We urge Government to review the inclusion of airside transit passengers.
“Every little bit of extra competitiveness that Government can deliver for aviation will help deliver vital growth for the whole of the UK economy.”
Meanwhile, Heathrow said it was used by a total of nearly eight million passengers in July, making it Europe’s busiest airport in the first half of the year, ahead of rivals such as Amsterdam Schiphol, Frankfurt, Madrid and Paris Charles de Gaulle.
The west London airport surpassed a weekly passenger total of 1.8 million for the first time last month, doing so for three consecutive weeks from July 8.
Venice in Italy and Larnaca on Cyprus were among the most popular destinations for people jetting off for summer sun.
Heathrow said it “performed well with no material impacts on flights” from issues such as the global IT outage or Just Stop Oil protests.
The airport’s chief executive, Thomas Woldbye, said: “Team GB’s performance in Paris has been an inspiration to the nation and to Team Heathrow.
“In July we were smashing a passenger record almost every single day and we’re chasing down our never-before-seen goal of serving eight million passengers in a single month.
“I’m proud that although there were a few potential challenges which could have caused us to stumble, our team remained focused on the prize of making every journey better and delivered a medal-winning start to the summer getaway.”
The airport announced last month that despite a fall in half-year revenues of 2.9%, it swung to an underlying profit of £178 million, from a £139 million loss a year earlier.