Heathrow, along with other major travel hubs, was hit by chaos over the Easter weekend. Passengers faced long queues and cancellations.
Nigel Milton, chief of staff and carbon at Heathrow, said passengers were partly responsible for the chaos.
He said: “What we have seen is that the rejects of hand luggage is about twice the level it was in 2019 because people have forgotten they’ve got to take liquids out, even though all the signs are there, even though we’re saying it to them.”
He added that some passengers had arrived with passports close to expiry or without the correct Covid documentation.
Although the UK has scrapped travel restrictions, many travellers still need proof of vaccination or travel tests for their holiday destination.
Milton said that issues were also caused by the Government’s sudden decision to scrap all Covid measures.
He said: “We were lobbying (the Government) hard to open up. But the speed at which the Government then unravelled it did take us by surprise.”
Staff shortages have led to some of the issues, as employees falling sick with Covid exacerbated existing shortfalls.
The airport is currently aiming to recruit 12,000 new employees in time for the busy summer period.
Milton added that 240 new staff were starting training every fortnight to start work at Heathrow.
The airport is also planning to reopen Terminal 4, which has been shut since 2020, in July to ease the chaos.
Milton said: “There’s a lot passengers can do to help themselves and help us by getting ready.
“It’s making sure, for check in they’ve got the right documentation, that they are ready.”
However, he shared that he expected that queues would last into the summer, in bad news for British tourists.
He said: “I think it’s going to be tough, because the opening of T4 means that Border Force will be spread over another terminal, our security colleagues will be too.
“So I think this summer is going to be uncomfortable again. There will be queues but there won’t be chaos.
“There will be queues which we will manage.”
Passengers can only take liquids of up to 100ml through airport security and liquids must be held in a single, transparent, resealable plastic bag, which holds no more than a litre.
Some airports, including Heathrow, offer the bags for free before security and it’s a good idea to pack items before joining the queue.
Each passenger can have one plastic bag and they must show the bag at the airport security point.
Liquids in containers larger than 100ml cannot go through security even if the container is not full.