What airlines don't tell you about flight delays

There's a lot that airlines don't tell you about domestic flight delays. Weather and mechanical problems are just some of the issues causing holdups and cancellations. As CBS News' Kris Van Cleave reports, many of the problem-plagued routes have some things in common -- things that could save you time next time you fly.

Larsen Jay knows what should be a quick flight from Chicago's O'Hare International Airport to Knoxville, Tennessee, often isn't.

"Delayed, delayed, delayed, and then they change their mind and it's delayed again," Jay said.

The idea is to get as many people where they need to go as close to on time as possible, and to do that, airlines have to delay or even cancel flights.

Forty-four percent of flights on the Chicago O'Hare-Knoxville route did not arrive on time last year -- the worst nationally. Here's why:

  • The route flies from a hub airport for two major carriers that is prone to delays from weather and congestion. Fifteen of the 20 worst on the list all came to or from O'Hare.
  • Typically all flights to Knoxville are small regional jets, which is the case for 17 of the 20 worst-performing routes.
  • They hold fewer passengers and make several stops during the day, increasing the likelihood of a delay, especially late in the day.

"If you are making a tight connection over a hub to a regional jet in the afternoon, you need to be very careful in planning your itinerary because odds are you are going to be late," masFlight CEO Josh Marks said.

Marks' firm estimates canceling an international flight can run nearly $43,000 for an airline, impacting hundreds of passengers. A regional flight can cost as little as $1,000 and affect closer to 50 people.

"What they are doing is trying to prioritize how to complete the maximum number of flights that they can, given the limited resources they have to work with," Marks said.

Inside United Airlines' network operation center in Chicago, teams from all aspects of the airline -- maintenance to meteorology -- work to keep 5,000 daily flights operating as on time as possible.

Jim DeYoung is the man in charge. He said the airline tries to isolate delays whenever possible.

"It's not only the people on that individual flight, it's the people waiting for that airplane. That airplane may have six or seven segments throughout the day... We want to minimize the impact on those down-line segments too and those down-line customers," DeYoung said.

MasFlight said about one-third of delays and cancellations result from maintenance issues. Those can't be avoided. But morning flights tend to be delayed less frequently. Direct flights eliminate the uncertainty of making a connection, as many of those happen at airports like O'Hare.

If there is severe weather in the forecast, call the airline well ahead of your flight. They may be able to reroute around it.