Air Canada passengers line-up at the baggage check-in counter at Pearson International Airport in Toronto April 13, 2012. Air Canada canceled at least 30 flights on Friday after what it called an "illegal job action" by some of its pilots, the latest example of tense labor relations at the country's biggest airline. The carrier, in a heated dispute with two of its key unions, including the one representing its 3,000 pilots, said it was exploring its options to deal with the disruption, which came after pilots reportedly called in sick even though they were fit to fly. REUTERS/Mike Cassese (CANADA - Tags: TRANSPORT BUSINESS EMPLOYMENT)