Heathrow Airport has extended its flight restrictions until 29 October, hitting families' plans for half-term getaways.
Previously the daily cap on passengers travelling through the airport - set at 100,000 - was due to end on 11 September.
The airport said on Monday that without a cap, it will not be able to safely and reliably handle its flight schedule.
Airline travellers across the UK have faced months of chaos, with disrupted and axed flights, paired with long waits at check-in, security and baggage collection.
The main reason for the problems has been a struggle to recruit new staff.
Heathrow claims that since the limits were introduced in July, there have been fewer last-minute cancellations, more punctual flights and shorter wait times for bags.
But airlines blame the airport - one of the busiest in the world - for failing to prepare for a bounce back in passenger traffic following the pandemic.
Some airlines could see the cap lifted sooner than October, Heathrow said in a statement, if "improved resource levels are evident and the airport continues to see sustained operational improvements".
But it pointed to the lack of ground handling crews as a key problem in resuming normal services.
Issues with these staff remain "a core constraint on capacity at the airport".
"Our primary concern is ensuring we give our passengers a reliable service when they travel," said Heathrow chief commercial officer Ross Baker.
"That's why we introduced temporary capacity limits in July which have already improved journeys during the summer getaway."
"We want to remove the cap as soon as possible, but we can only do so when we are confident that everyone operating at the airport has the resources to deliver the service our passengers deserve," he added.
Last week, Heathrow's chief executive John Holland-Kaye said that the airport was beginning to recover from the travel chaos of recent months.
Thousands of jobs were lost in the aviation industry during the pandemic, when travel restrictions saw most flights grounded - and now there is a race to recruit new workers to accommodate the resurgence of holidaymakers.
Training those staff up and getting them the necessary security clearance has also been a lengthy process, airport bosses have said.
Heathrow has been among the worst-affected.
In an update on Thursday, Mr Holland-Kaye said: "Passengers are seeing better, more reliable journeys since the introduction of the demand cap."