While Air Canada says it would not negotiate with the union until flight attendants return to work, CUPE says the two sides were in discussions Monday night with a mediator.

If you've been following the Air Canada strike throughout its twists and turns, you've likely heard the term "ground pay," or noticed flight attendants holding signs decrying unpaid labour. But what is that unpaid work?

The Canadian Union of Public Employees says a strike by 10,000 flight attendants at Air Canada will continue, defying an order from the Canada Industrial Relations Board that it provide public notice by noon ET that it had ended the strike.