Passengers using several airports in Germany had their flights disrupted for a short time when security staff staged a wildcat strike over pay and conditions.
The trade union Verdi said about 1,000 staff were called out at short notice. A spokesman said their demands include fair work contracts for 15,000 employees, and a switch from temporary employment to permanent jobs.
The main impact of the action, which lasted just a matter of hours, appeared to be restricted to delays and long queues for air travellers.
A spokesman for Germany’s largest airport, Frankfurt, said the action had not caused any disruption there.
Talks between the union and employers are due to resume in January.