Air Canada flight attendants ’ strike entered its fourth day on Tuesday, causing widespread disruption for hundreds of thousands of summer travellers, despite the union confirming that talks with the airline have resumed.

Air Canada flight attendants extended their strike into a fourth day on Tuesday, although the union said both sides had resumed talks as hundreds of thousands of passengers had flights canceled during the busy summer travel season.

Air Canada and the union representing 10,000 striking flight attendants were holding early discussions on Monday night, the union said in a statement, the first such talks in nearly a week.

Lawyer Sundeep Gokhale says there is a ‘high possibility’ that the Canada Industrial Relations Board will get involved if Air Canada flight attendants strike.