Passengers face major delays at the worst possible place with unions threatening to strike at more than a dozen airports in the UK.
The Unite union has threatened to shut down Heathrow and bring "check-in chaos" for Easyjet passengers at London Stansted, with workers due to walk out from next week.
It has also warned Gatwick faces a "summer of disruption" reports the Daily Mail.
Unite announced they will stage three 48-hour walkouts during July and August. However as unions are legally obliged to give at least two week's notice of industrial action, the strike would take place from August, if it does go ahead.
Its 4000 members - including security staff and maintenance workers - are currently voting on whether to strike at Gatwick Airport in a separate dispute over pay.
If they back industrial action, the walk out could begin as early as mid August, in the height of the summer holiday season.
Not to mention that thousands of British Airways pilots are also voting over whether to strike over pay.
The airline operates at 14 UK airports, including Heathrow, Gatwick, Stansted, Leeds Bradford, Manchester, Newcastle, Newcastle, Inverness, and Edinburgh.
London City is the only airport that would not be affected as their pilots are on different contracts.
The ballot closes on midday on Monday. The British Airline Pilots Association is expected to announce the result later that day.
The union has claimed low paid workers at Heathrow, Gatwick and Stansted - many of them employed by private contractors - have been given meagre pay rises.
Heathrow said it has offered a pay hike of 4.6 per cent to 70 per cent of front line workers, with the remaining workers receiving at least 3.2 per cent.
Last weekend UK transport secretary Chris Grayling said: "Whatever the rights and wrongs of the dispute, there can't be any justification for actively trying to disrupt people's summer holidays at such a busy time of the year."
Separately, climate change activists Extinction Rebellion have threatened to shut down Heathrow for up to 16 days this autumn by flying hundreds of drones at head height around the airport.
Here's what is planned so far
More than 4,000 workers across Heathrow could bring chaos to the airport by walking out on the following days:
July 26, July 27, August 5, August 6, August 23, August 24
Unite said it was balloting workers to determine their wishes. A possible strike then "delays and disruption" could take hold of the airport "later this summer", Unite said.
Easyjet check-in staff have announced 17 days of strikes on the following dates:
July 25-29, August 2-5, August 9-12, August 16-19, August 23-27
Unite said 43 staff working at check-in desks had voted unanimously for walkouts.
A Unite regional officer said there was "no getting away" from the fact that the action would cause "severe disruption" to thousands of Easyjet customers using Stansted.