Gatwick and Stansted are set to be hit by strikes on August 25 and 29 in a dispute over pay which could spread to Manchester, Birmingham and Newcastle airports.
Workers employed by Swissport have rejected a “paltry” 3% pay offer which unions complained was well below the rate of inflation.
The company was also accused of removing sick pay for the first three days of any absence due to illness, including industrial injury.
Members of Unite at Gatwick and Stansted will take part in the strike, while GMB members at Stansted will also walk out on the same days. Unite will announce a ballot result among its Swissport members at Manchester airport next week and said workers in Birmingham and Newcastle airports will also be balloted.
National officer Steve Turner said: “This pay offer is an insult to professional, hard-working men and women who have to operate in extremely difficult conditions.”
A spokesman for Swissport said: “Swissport believes that a fair offer has been made to the unions in the light of the current economic climate that reflects the cost of living increase.
“Swissport is working with the airport operator and the customer airlines to minimise disruption to the travelling public.”
The GMB said its members at Stansted will also strike on August 25 and 29 after voting by 9-1 in favour of industrial action.