Civil Aviation Authority staff working at Gatwick Airport and Canary Wharf have begun a two-day strike over pay.
Members of the PCS and Prospect unions walked out this morning.
The unions say they are escalating action, which began earlier this year in protest over a pay offer of 3-4%. PCS members first walked out in January, then held a joint strike in February with members of Prospect.
PCS General Secretary Fran Heathcote said: “Our members are proud to work for the CAA, keeping our airspace safe, but pride doesn’t pay the bills.
“They deserve be treated fairly and paid fairly. Until they are, we’ve been left with little option but to escalate this dispute.”
Members of the Prospect union employed by the CAA have been working to rule since January.
Prospect Deputy General Secretary Rachel Curley said: “Despite our ongoing industrial action the CAA has still not come to the table with an offer our members can accept so we have no choice but to escalate to a day’s strike.
“There is still time to avoid further industrial action which will be damaging for the industry but the employer needs to restart good faith negotiations.
“This is not an issue that is going to just go away and if it continues it will start to impact airlines causing delays to planned upgrades with a knock-on effect felt by passengers.”
The CAA previously said the industrial action would not affect flights.
