I believe shorting AC to be a play on many macro ideas. Overall the market looks to be heading lower bringing everything down. AC just had a crashed plane in eastern Canada which is being investigated. Oil may be bottomed may be not but if it does go up that will have a negative effect on AC. There is a cutting of excess spending in Canada from a personal to corporate level, which includes travel. Currently it is trading near the top of it's range ready for a correction.