Air Canada's new offer features London, Rome, Beijing, and Shanghai. Book tickets by January 17.
United's London fares are valid for travel through late March. Departure cities include Chicago, Los Angeles, and New York.
Delta's new Europe deal features Frankfurt, Nice, and Prague. Book tickets by January 29.
Book Spirit's sale fares by 11:59 p.m. ET on Saturday. Destinations include Atlantic City, Orlando, Montego Bay, and San Juan.
