Egypt’s national air carrier grounded its international flights from Cairo Friday because of a 12-hour strike by the company’s flight attendants, AP reports.

Hundreds of passengers crowded into the airport, some protesting the disruption of their travel plans and arguing with airport staff. Security checkpoints were set up on the road to the airport to keep passengers away, preventing a bigger backlog because of the strike that began after dawn Friday.

Some passengers dodged the roadblocks, carrying their luggage and walking to the terminal.

Company officials said as many as 20 international flights were cancelled, but domestic flights were not affected. EgyptAir estimated its losses from the canceled flights by midday at $10 million.

The flight attendants are demanding improved working conditions.

EgyptAir cabin crew employees have long complained of shortage of staff, accusing the company of using the minimum number of attendants, undermining services. The attendants are calling on management to establish a separate unit in the company for the cabin crews, along with an increase in their benefits.