Think flight times are being padded? They are

— -- The Earth hasn't expanded significantly. The seismic plates under North America haven't shifted dramatically. And quite a few commercial aircraft are faster than ever. But it's still taking longer to fly on many domestic routes — and flight times are growing longer, not shorter.

Don't believe it? Check out the chart below and see just how much scheduled flight times have been stretched since 1995. For airline executives facing chronic delays on certain routes, the answer has been to pad those flights' "block times" by lengthening the total number of minutes the aircraft is expected to operate, all the way from the gate at Airport A to the gate at Airport B.

As one airline operations manager said to me a few years ago: "The airlines are no more on-time than they used to be, but they're better at covering it up."

Back to the future

Throughout most of the history of aviation, flight times naturally decreased as navigational technology improved and airplanes grew faster. But now, at congested airports around the nation, the technological sweet spot is long past. That's not because airplanes have gotten slower; in fact, Boeing says its new 787 Dreamliner will cruise at Mach 0.85, similar to the fastest wide-bodies. Rather it's because the situation is akin to a Ferrari F430 stalled in bumper-to-bumper traffic on a clogged interstate. Even the supersonic Concorde was subject to the same taxiing delays endured by the slowest turboprops in New York, London and Paris.

The problems often aren't with the flight times, they're with the block times. That's why Gerard Arpey, CEO of American Airlines, recently told shareholders his carrier was making "strategic adjustments" in an effort to improve customer service. He was quoted as saying: "Among other things, we adjusted the way we schedule our aircraft, flight attendants and pilots. We increased our block times, as well as the time planes spend on the ground between flights in many instances." The result? According to the U.S. Department of Transportation, American's on-time performance for the 12 months ending in April was 74.2%, up from 67.2% during the same period a year ago.

American is not the only airline that has increased block times. In fact, throughout the year airlines continue to expand and contract—though they usually expand—the length of time you're scheduled to be onboard. So you may have a greater chance of arriving on time now. Even if it takes longer to get there.

Who reports delays?

Among regulators, aviation analysts, consumer advocates, journalists and travel agents, the DOT's monthly Air Travel Consumer Report is the foundation for all who evaluate the airline industry's customer service performance. Twelve times a year, the report's extensive charts detail the on-time performance of the nation's largest carriers, and that information is used in countless ratings and rankings.

But have you ever wondered where those numbers come from? After all, the DOT doesn't dispatch an army of inspectors to roam the nation's airports, hovering underneath jet bridges, consulting stopwatches and clipboards. Actually, it's a self-reporting system. In fact, each month domestic airlines voluntarily provide more data than the DOT even requires.

The ways in which airlines record departure and arrival times can vary widely. Today, most rely on a tool known as the Aircraft Communications Addressing and Reporting System (ACARS), a digital system that transmits information via radio or satellite. You've probably been reading about ACARS lately, since this was the technology that relayed messages—perhaps conflicting messages—indicating system failures onboard Air France Flight 447 just prior to the loss of all communication with that aircraft over the Atlantic Ocean earlier this month. Another reporting option is a Docking Guidance System (DGS), such as those that employ laser-based technology to allow pilots to self-park aircraft at a gate. Still another method is for flight crew or ground crew personnel to transmit the departure and arrival times via radio, electronic, or even written communiqués.

There's another nuance to be considered, particularly since many delays occur on taxiways after airplanes have pushed back on schedule. Within airline circles, on-time performance is measured in four ways, known as O-O-O-I: Out (of the gate), Off (of the ground), On (the ground), and In (the gate). What's more, airlines may employ separate systems for recording out/in and off/on times. Interestingly, in 2007 the DOT proposed to collect "additional data elements" from ACARS when flights are canceled, diverted, or return to the gate; the DOT stated this information would be used to obtain "a more accurate portrayal of on-ground delays."

Yet another complication is that an electronic system can trigger a "departure" based on many different parameters: when the passenger and/or cargo doors are closed, the operating beacon has been switched on, the brake has been released, or the airplane actually begins rolling.

Currently airlines have the option of filing electronically or manually and at this time there aren't any changes planned for the reporting system, according to Bill Mosley, a spokesman for the DOT. Among the 19 airlines reporting on-time performance each month, the DOT states the following:

• 13 use ACARS exclusively (AirTran, American Eagle, Atlantic Southeast, Delta, ExpressJet, Frontier, Hawaiian, JetBlue, Northwest, Pinnacle, Southwest, United, and US Airways)

• 2 use ACARS and DGS (American and Continental)

• 1 uses manual reporting systems (Comair)

• 3 use ACARS and manual reporting systems (Alaska, Mesa, and SkyWest)

A critical side note: Personally I think it's counterproductive to break out the on-time performance of commuter airlines separately from their major carrier partners. No one books a scheduled flight on Comair — they book a flight on Delta and are carried on Comair operating as Delta Connection, so Delta's on-time performance should reflect both carriers' statistics. Of course, the relationships between major airlines and their commuter partners also have far-reaching implications on safety, security and consumer issues, but those are other columns for other days.

The fact is many of us who write about the aviation industry quote the monthly DOT data as if they were sacrosanct. I myself have referenced these statistics dozens of times over the years, often in this column, though it's always been with somewhat of a nagging feeling. Because I recall my days working in airline flight operations management and I remember how such numbers were easily—and often—manipulated.

Delay? What delay?

Experts tell me it's harder to alter data culled from electronic ACARS or DGS systems. But it's that term "manual reporting system" that raises a few questions. I worked at smaller airlines in which various work groups—maintenance, passenger service, catering, crew scheduling, dispatch—would argue to the point of shoving matches over who stepped off the aircraft last, and whether or not the plane pushed back on time. At some airlines, pilots made this critical decision; at others it was made by dispatchers, operations personnel, or ground crews. But I often thought that human nature being what it is, those who could be responsible for generating a delay should not also be responsible for declaring a delay. On many occasions I witnessed an airline report a flight as departing on time when in fact it did not.

Then there was a stretch when the pilots at the Pan Am Shuttle were in some tough contract negotiations. I was overseeing at least four departures every hour on the half hour, and internally we considered anything more than five minutes a delay—that is, any flight that pushed back from the gate more than 35 minutes past the hour required me to generate a company report. Suddenly, on a clear blue day with no weather or air traffic control problems, multiple crews began calling in their off-blocks times, and flight after flight was reporting 36 minutes past the hour. Our on-time performance, critical for a shuttle operation catering to business travelers, was plummeting overnight—and in every instance by just one minute. After an entire shift of transcribing six-minute delays onto an electronic spread sheet, the next day I was told by a supervisor that the solution was simple: From then on, all flights calling in at 36 minutes past the hour would be recorded as 35 minutes past the hour. And voila, our imaginary delays instantly evaporated.

That wasn't the only way to fudge an on-timer. Because the Shuttle employed Boeing 727s, we often made use of that aircraft's built-in aft staircase to board and deplane passengers without the use of a jet bridge. On days when there were extensive air traffic control delays between New York and either Boston or Washington, we would push the aircraft just a few feet off the blocks, declare it on time, and then lower the aft stairs to allow passengers and crew to leave the plane if the delays lengthened, all while the airplane sat just off the gate with the engines shut down. It actually was a much better alternative than holding passengers "hostage" during lengthy taxi delays.

Let's be clear: I have no evidence that today's airlines fudge their on-time numbers the way they often did in the past. In fact, I've spoken to front-line experts in the field who tell me it's gotten much harder in recent years to file erroneous reports, for reasons ranging from sophisticated travelers being able to monitor weather and system delays to pilots' pay being tied to ACARS data.

While an airline may or may not be able to fudge its departure times, it's just about impossible to conceal a late arrival (which by the way, the DOT defines as 15 minutes or more). So remember: When you research a carrier's on-time performance, the best advice is to focus on arrivals rather than departures. The reality is that most passengers aren't concerned about leaving on time nearly as much as they are about getting there on time.

And the airlines know this too. That's why more and more flights have that little extra wiggle room built right in.

EXPANDING BLOCK TIMES(all comparisons are with closest scheduled departure times)

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Bill McGee, a contributing editor to Consumer Reports and the former editor of Consumer Reports Travel Letter, is an FAA-licensed aircraft dispatcher who worked in airline operations and management for several years. Tell him what you think of his latest column by sending him an e-mail at USATODAY.com at travel@usatoday. Include your name, hometown and daytime phone number, and he may use your feedback in a future column.