Delta Air Lines cancelled more than 800 flights due to Hurricane Irma, now a tropical storm blowing through Atlanta. The U.S. airline said Irma is bringing strong crosswinds that could make landing dangerous. Irma, ranked as one of the most powerful hurricanes recorded in the Atlantic, hit a wide swath of Florida over the past few days. Delta operates the world’s largest airline hub at Hartsfield-Jackson, and flight cancellations can disrupt travel plans of tens of thousands of people from around the country and the world. At the same time, Delta is working on resuming service to airports in Florida that got hit by Irma.