The airports in Salt Lake City, Portland, Ore., and Minneapolis/St. Paul lead the Travel + Leisure list of the best airports in the U.S. for on-time performance. Meanwhile, airports deemed the worst offenders are concentrated around the toughest markets, including New York, Chicago and Atlanta. Overall, airports lowered their percentage of delayed flights with only one airport reaching 30% this year. Last year, four airports had flight delays 30% of the time.