Caesars Entertainment will tap the Montreal market for gambling customers by combining hotel packages with new charter flights between Atlantic City and upstate New York. Service from Plattsburgh, N.Y., to Atlantic City International Airport will begin April 23 and run through August using jets operated by Republic Airways, which handles air charters for Caesars’ casino hotels across the country. Garry Douglas, president of the North Country Chamber of Commerce in Plattsburgh, noted that the summer charter flights will extend Caesars’ reach into the potentially lucrative Montreal metropolitan market consisting of 3.5 million people. “We are Montreal’s U.S. airport,” Douglas said…