Flight delays could hit Stansted Airport during the first May bank holiday weekend.
Strikes will go ahead at the airport after a substandard pay offer was rejected.
Around 100 ABM workers, who support passengers with disabilities, will walk out from May 3 to May 6.
Unite has warned that the action will cause delays to flights, with longer boarding times expected.
Sharon Graham, Unite general secretary, said: "ABM staff do a vital job for passengers at the airport, yet they are struggling with low pay while their employer makes huge profits.
"This situation is unacceptable and workers at ABM continue to have Unite's full support."
Many of the workers are paid below the London living wage of £14.80.
They also claim that workloads have increased along with passenger numbers.
In January, more than 1.89 million passengers passed through the airport, a two per cent rise on the same month last year.
ABM, a global services company, reported $2.2 billion in revenue in March, up 6.1 per cent on the previous year.
Steve Edwards, Unite regional officer said: "Workers at ABM are increasingly given bigger workloads and deserve pay that reflects this.
"Their employer can afford to come back with an offer workers would accept and could end this dispute easily by doing so.
"But until then, Unite members will strike until their voices are heard."
A previous strike planned for April 17 to 20 was postponed to allow workers to vote on a last-minute pay offer.
An ABM spokesperson said: "We are disappointed that Unite the Union has confirmed, once again, its intention to take industrial action, including over the bank holiday.
"This follows a shortfall of just two percentage points in the vote on our structured pay increase - an offer that significantly exceeds the current rate of inflation.
"Through comprehensive contingency planning, we will continue delivering services throughout this period with all roles covered, and additional operational and management support in place.
"Our focus is on maintaining safety, operational resilience, and service continuity as far as possible for the passengers who rely on our team every day.
"We remain open to constructive conversation with Unite the Union and hope that a resolution can be reached in the best interests of our employees and the passengers we serve."