UPDATE: Airline 3-hour tarmac delays virtually gone; PHL's much-improved on-time performance

This post is UPDATED below with good news about PHL's on-time performance in August.

Airlines fought hard for years to keep federal regulators from imposing hard-and-fast rules on long tarmac delays, warning that cancellations would go up. But four months into the imposition of heavy fines for stranding passengers for three hours or more on planes, either the airlines have been really lucky, or the dire predictions are turning out to be overstated hyperbole, or both. The U.S. Department of Transportation reported this morning that one -- yes, one -- flight in August for the 18 airlines subject to the rules was delayed for more than three hours. In August 2009, 66 flights were delayed three hours or more, including one stranded overnight in Rochester, Minn., that helped push DOT to adopt the rules.

What happened to cancellations? They amounted to 1 percent of scheduled flights, compared with 1.4 percent last year. Since the rules took effect April 29, eight flights have been delayed three hours or more, compared with 529 in the same four months last year. Let's let the numbers speak for themselves.

UPDATE on PHL: The airport's on-time performance this month continues recent trends that could cause PHL to lose its reputation as "one of the most nation's most delay-prone airports. I, and many other area writers, have used that term in articles and blog posts for years because it was accurate. Not anymore. Philadelphia ranked No. 11 out of 31 major airports for on-time departures in August; for arrivals, it was in 13th place. Almost 83 percent of all flights were on time in the month.

US Airways, the largest PHL carrier, led the way with 85 percent of its flights arriving on time. No. 2 carrier Southwest got 82 percent of its flights to the gate on time. Here is today's Inquirer story on how PHL and US Airways did in on-time peformance and other measures of service. In a turnabout from previous years, also, here is a story about how Southwest turned in the worst on-time performance in September, while legacy carriers had some of the best records, according to FlightStats.com, which reports on actual flight operations sooner than DOT does.

For many years, PHL seldom ranked above No. 20 in the DOT tallies, and often was in the last four or five in on-time performance. PHL will have lower rankings for the full year because of lots of delays earlier in the year, but this is still good news.

Here is a news story that emphasizes the bad news in the August stats: Complaints were way up. For those who need lots of detail on flight operations, here is the Air Travel Consumer Report for October, with data from August.