LONDON — British Airways says it can run its full holiday schedule on Christmas and Boxing Day even if a planned cabin crew strike goes ahead.

Chief Executive Alex Cruz said Monday that detailed contingency plans are in place so that flights can operate as normal.

He urged the Unite union to call off the planned strike. The dispute involves pay for staff members who have joined the airline in the last six years, and negotiations continue.

The United Kingdom faces a Christmas of discontent as labour unions threaten to disrupt airports, rail services and mail deliveries.

The Unite union and aviation services company Swissport announced negotiation plans intended to avert a Dec. 23 walkout by 1,500 baggage handlers, check-in staff and other workers at 18 regional airports from Belfast to Bournemouth.

At British Airways, a fourth of the airline’s cabin crew members are planning a two-day strike starting on Christmas, Dec. 25. British Airways condemned Unite’s timing and vowed to ensure that all customers reached their holiday destinations.

“This calculated and heartless action is completely unnecessary and we are determined that it will fail,” the airline said in a statement.

McCluskey countered that the airline “needs to come to the table with a positive offer.”

Rolling strikes by two unions at Southern Railway already have disrupted much of England’s train services this month, with worker protests over cutbacks in overtime scheduled to go on until Jan. 14.