Continental Airlines is joining the buy-on-board menu wars with specialty cocktails. The airline announced Wednesday that it will start selling mojitos, pomegranate martinis and Red Bull energy drinks. Starting Thursday, customers will be able to buy the drinks with alcohol for $9 and without it for $3.Continental joins other airlines in getting creative with the drinks they’re selling, going well beyond mini bottles of booze. Southwest Airlines sells a $4 screwdriver, a mix of vodka and orange juice. Delta sells a $7 Five O’clock Somewhere, a mix of rum, orange juice and cranberry-apple juice. Though airlines charge for alcoholic beverages,...