Holiday passengers may not get food, drinks or even smiles, on their Cathay Pacific flights as the cabin crew threaten to protest over a pay dispute with the Hong Kong-based airline, a union official said Thursday.

The Cathay Pacific Airways Flight Attendants Union is demanding a 5% pay increase, but was offered 2% and a 13th month bonus instead after the airline posted a first-half loss of 935 million Hong Kong dollars ($120.5 million).

General Secretary Tsang Kwok-fun said the union would carry out industrial action that could delay flights and stain the airline’s service.

“We may not provide alcoholic drinks to our passengers, or we may not even provide meals to passengers,” Tsang told AP, adding the union would advise travelers to bring their own food and drinks.

Flight attendants could also withhold smiles and greetings from passengers. “We cannot smile because of the situation, because of how the company treats us,” Tsang said.

The union is also considering working to rule, which involves doing no more than the minimum work required in contracts and strictly following safety regulations, such as enforcing stern size limits on hand luggage.

Cathay said it is willing to hold further talks with the union and took out ads in Hong Kong newspapers on Thursday. “We fully understand how important it is not to disrupt passengers at this busy time,” the airline said.