Industrial measures at Glasgow airport are to be escalated following a breakdown in talks to try to resolve a dispute over pensions.
On Friday, Unite announced that a four-hour stop on June 14, between 4 and 8, would be put into action already scheduled at the airport.
Community members voted 95% for favor, with an increase of 75%, in April to take action over spring and summer after the airport decided to close the final salary.
The trade union said that the decision to close the pension scheme broke an agreement on counseling, conciliation agreement and arbitration (Acas) that was made in 2016.
The airport is part of the AGS Airports Limited group, which also owns Aberdeen and Southampton airports.
AGS rejected the association's claim and said that a copy of the agreement that Unite had allegedly been breached had been shared with employees showing that this was false.
Planned industrial actions last month were suspended after "progressive calls" which saw the company table offer a 3% offer for employees in Aberdeen and Glasgow.
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However, Unite said it added additional stops in response to Glasgow Airport and withdrawn from negotiations.
Two 1[ads1]2-hour strikes on June 7th and 10th between 7pm 04.00 to 16.00 had already been arranged.
In a statement from AGS Airports earlier this week following Unite's industrial action notice, the company said it had been involved in talks since January, but claimed that there had been "no will whatsoever" from the trade union's involvement in a constructive manner.
The company also said that the increased 3% offer – an increase of the initial 1.8% suggested – was a "significant improvement" in line with the demands of the unions.
The final salary plan, the company says, is "simply unaffordable" with the cost of the company due to rising to 24.7% per employee.
Pat McIlvogue, Unite Regional Industrial Officer, said: "Unite in response to Glasgow Airport's withdrawal from the pension scheme negotiations added a further halt.
"It is confusing why the AGS leadership appears to be willing to escalate this dispute. Unite entered into an attempt to resolve this conflict and we are still willing to speak.
"In fact, Unite invited AGS for further conversations this week, but this has been faced with a wall of silence.
"Unless the company returns around the negotiating table, we cannot rule out that additional dates are added to those already announced in a dispute produced solely by the AGS management."
A spokesman for the AGS said: "We are very disappointed that Unite has announced a further date for industrial action, but would like to take this opportunity to assure our passengers that robust contingency plans will be in place to ensure that will be business as usual at Glasgow Airport Friday 7, Monday 10 and Friday 14 June.
"We have been in talks since January, and despite the fact that we meet Acas, there is still no willingness for Unite to engage in a constructive dialogue. We have made a significant improvement on our initial payment offer that was increased from 1.8% to 3% in line with requirements, rejected by Unite without further consultation with members, and the Union continues to deny them the right to make a 3% bid offer.
"Regarding our final wage pension, it is simply prohibitive with the cost of the company due to rising to 24.7% per employee. We made a generous compensation package for the remaining members, which was again rejected by Unite without first consulting their members.
"Unlike the association's last statement, no one has contacted this week, but as always, we remain open to continued dialogue with Unite to resolve this conflict."