Air Canada is warning that a pilot strike at a major European airline could cancel flights.

Air Canada said it has been advised that Lufthansa-operated flights scheduled between April 2 and 4 are subject to cancellation.

The union representing the pilots called for the strike at the end of March due to a long-running pay dispute. Among other issues, the Vereinigung Cockpit union said Lufthansa had failed to make a "negotiable offer" during two years of pay negotiations.

Lufthansa is Germany’s largest airline.

Air Canada says customers with tickets booked on Lufthansa flights, including “codeshare” flights ranging from AC9000 to AC9719, may be affected by the disruption. It said that customers most likely to be affected are those booked on connecting flights going through Frankfurt and Munich.

Air Canada says it has already begun to rebook passengers on other airlines, and is allowing customers to delay travel plans up until September 30. Travel arrangements can be changed by calling the airline or visiting its reservation website.

The strike at Lufthansa is expected to cancel some 3,800 flights worldwide, affecting more than 425,000 passengers.