Heathrow Airport workers will hold a 24-hour strike over pay and terms on Tuesday in the first of a series of strikes.
Unite members, including firefighters and security guards, will also cease work on December 14th, 17th and 18th unless the dispute is resolved.
The union said it had “serious concerns” about the safe operation of Heathrow during the series of strikes, but the airport said it had contingency plans.
Engineers, baggage companies, central terminal operations, and land and air side workers will also be involved in the campaign.
Wayne King, Unite officer, said: “Unite has serious concerns that Heathrow Airport (HAL) will not be able to operate safely during the impending strikes. Unite urges the Civil Aviation Authority and the Occupational Safety and Health Officer to ensure that HAL’s emergency planning has not compromised the level of safety and to ensure that Unite is involved in these discussions.
“There are thousands of passengers and workers who will use the airport during the strike and they need cast iron guarantees that the airport will operate in a perfectly safe manner.
“Heathrow employees are very proud of their work and have continued to work throughout the pandemic. They had to put their own health at risk to care for passengers who developed Covid.
“They are taking strike action as a last resort, as cuts in their wages of up to a quarter will force them into poverty.
“Unite offered a variety of solutions to reduce costs and avoid industrial action, all of which HAL rejected out of hand.”
A Heathrow spokesman replied: “It is very disappointing that Unite decided to go on strike in the air transport sector during the worst of the crisis.
“Our focus was on protecting jobs. That’s why we’ve offered any frontline colleague who wants a job at a market salary above the London Living Wage, even though our company has lost more than £ 1.5 billion to date.
“We don’t believe this strike action is necessary, but we have activated extensive contingency plans to keep the airport open and functioning safely during this period.”