Tarmac Delays Down, Cancellations Up

The Department of Transportation (DOT) has released its traffic numbers for July, and is predictably trumpeting another month with virtually no three-hour (or longer) tarmac delays. Well, three, to be exact, a miniscule .1048 percent of all flights in July. Last July there were 161 tarmac delays of three hours or longer.

What about cancellations? The DOT says they rose “slightly,” from 1.2 percent last July to 1.4 percent this July. But while percentages can be instructive, it’s worthwhile to look at the raw numbers:

• July 2009: 580,134 flights; 6,838 cancellations; 1.2 percent
• July 2010: 570,788 flights; 8,170 cancellations; 1.4 percent

So, July 2010 saw 1,300 more cancellations despite there being nearly 10,000 fewer flights. What does this mean? No idea. CrankyFlier points out that Delta had a really bad month for cancellations, so maybe the numbers would look better if Delta had its act together.

Still, with three months of data on record since the tarmac delay rules took effect, a pattern is beginning to emerge: Tarmac delays have all but disappeared, but cancellations have crept up. In May, the first full month with the new policy, cancellations jumped to 1.2 percent, from 0.9 percent in May 2009. Cancellations then rose from May to June, though June 2010 was on par with June 2009.

I’ve been saying all along that it’s too soon to draw sweeping, final judgment on the DOT’s tarmac delay rule. We need a full year of data before we can extrapolate any meaningful conclusions.

And yet, the first three months of data aren’t encouraging. At some point, hopefully we’ll get a more in-depth look at what connection, if any, there is between the regulations and cancellations. The possible correlation between tarmac delays and cancellations could be merely a coincidence, but absent definitive evidence from the DOT or airlines themselves, it’s difficult to tell. A few more months of conspicuous cancellation numbers, however, will be impossible to ignore.

Readers, what do you think is going on here?