Overall, Milecards found that 40 percent of the U.S.'s top 50 airports see increased delays during the summer. Those mucky airports include major hubs in Atlanta, Boston, both the Dallas airports, New York City's JFK, Orlando, San Antonio, and all three airports near Washington D.C.
At the other end of the spectrum, Kahului and Honolulu were found to be the most reliable. Those numbers aren't quite as grim, with 88 percent of flights arriving on time in Kahului and 86.5 percent in Honolulu. On the mainland, Salt Lake City leads the way (third overall) with 85.3 percent of flights landing as scheduled. In the Midwest, Minneapolis (79.6%) and Detroit (79.2%) were the most reliable.
Take a look at more in-depth numbers about the percentage of flights that arrive on time below.