BOSTON — A major winter storm brought some of the coldest temperatures of the season and blanketed a wide swath of the country in snow as it wreaked havoc on air travel and caused dangerously icy conditions throughout New England on Sunday. The National Weather Service issued winter storm warnings or advisories for part or all of at least 15 states stretching from southeast Missouri to the northern tip of Maine ahead of the weekend storm. More than 1,500 flights were canceled nationwide Sunday, with Boston’s Logan Airport among the hardest hit, according to FlightAware, a flight tracking company. Typically bustling security lines, ticketing counters and baggage claims were largely deserted Sunday morning at Logan Airport, but some stranded passengers lingered. Xavi Ortega, a 32-year old engineer from Spain, slept overnight at the airport with his wife after their 10:30 p.m.