According to analysis by the company Lets Fly Cheaper, air travelers are more likely to leave the gate late if they choose United Airlines over other carriers.
United Airlines ranked last in terms of timeliness on a list of 15 major carriers, using federal data from January to September of this year. The company's flights were on schedule roughly 76.5 percent of the time.
Just ahead of United in terms of punctuality were Express Jet Airlines (76.72% on time); American Airlines (77.86%); Frontier Airlines (79.12%); and JetBlue Airways (80.41%).
Express Jet aborted the most flights by far, with more than 10,000 cancellations in the nine-month time period of the study. The air carrier American Eagle was second-worst with 7,781 cancellations. Other offenders included SkyWest Airlines (7,662); American Airlines (7,152); and Southwest Airlines (6,159).
According to Lets Fly Cheaper, many delays and cancellations are due to the weather and air traffic control problems, but others can be blamed on the airlines themselves. The company said airlines sometimes don't staff enough crew members, and Federal Aviation Administration rules limit overtime hours.
"If one crew member reaches their maximum duty time, it's a ripple effect on the entire flight while the airline frantically attempts to replace that crew member. This causes a delay and in some cases a cancellation if a replacement can't be found," said Lets Fly Cheaper marketing director Sean Delanty, in a written statement.
Hawaiian Airlines was the shining star of the report. The carrier's flights were on schedule 93.15% of the time, with only 48 flights cancelled.