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 union for 10,000 striking Air Canada flight attendants said Monday they won't return to work even though the strike, now in its third day, has been declared illegal. The strike at Canada's largest airline is affecting about 130,