In this file photo, British Airways planes are parked at Heathrow Airport in London. Image Credit: AP

British Airways has extended a halt on ticket sales on short-haul flights out of London Heathrow airport by another week to August 15, adding to the summer's escalating travel chaos.

The extension of the moratorium comes just a day after the unit of IAG SA blocked ticket sales though August 8, blaming daily passenger capacity limits imposed by Heathrow to help cope with a staffing crisis. The carrier said it was halting sales to "maximise rebooking options for existing customers, given the restrictions imposed on us".

Heathrow, which has previously blamed insufficient airline staffing for chaos at the hub, on Tuesday suggested that delays were being caused by a disproportionate increase in leisure passengers. The airport operator said that vacationers, unfamiliar with travel rules, were taking liquids in their carry-on bags, forcing additional checks that "slow down the flow through security for all passengers".

Airlines and airports across Europe are struggling to meet demand that's rebounding strongly from the coronavirus crisis, with the London hub warning last week that the situation could persist through next summer.

BA has already canceled about 13 per cent of planned capacity this summer due to a shortfall in its own employees and Heathrow's limit of 100,000 daily departing customers, imposed on July 12.