Why airlines won't tell you how long the flight is

The U.S. State Department's two cautionary alerts mean very different things. (iStock)

Whether you always get to the airport hours before your flight or you waltz in minutes before cut-off time, you still spend more time waiting than you should.

The arrival and departure times airlines share with their customers often don’t match how long an aircraft actually needs to spend in the air. Airlines exaggerate how long a trip will take so that even when there’s a delay, the plane still arrives “on time," a strategy known as “schedule padding.”

The Telegraph reported that between 1996 and 2015, the allotted time for a flight from London’s Heathrow airport to Scotland’s Edinburgh has increased significantly, despite improvements in technology, almost entirely due to schedule padding. An AirTran Airways pilot confessed to Reader’s Digest that “airlines really have adjusted their flight arrival times so they can have a better record of on-time arrivals, so they might say a flight takes two hours when it really takes an hour and 45 minutes.”

To make matters worse, the definition of “on-time arrival” isn’t all that it’s cut out to be. Flightstats.com, a site that issues awards for on-time performance (OTP), counts every flight that lands within 15 minutes of its stated arrival time. Even with that generous definition of on-time, airlines try to account for everything that could possibly go wrong.

“We regularly review our flight plans and timings to ensure that we can meet our published departure and arrival times and customers can plan their journeys accordingly,” a British Airways spokesperson told the Telegraph. “The weather, type of aircraft, air traffic control restrictions, airport infrastructure and geopolitical considerations will all play a part in the decisions we take about whether to increase or decrease each route’s published flight time in our schedule.”

While there’s still room for improvement when it comes to the way airlines manage their flight schedules, 15 minutes really isn't that big of a deal, all things considered — just don’t be too impressed next time your flight arrives on schedule.

This article originally appeared on Travel + Leisure.