SFO
As I write this post, it’s not a great weather day for San Francisco International Airport — to put it mildly.

It’s a cool, very cloudy day, and with the airport’s parallel runway configuration, that means they can only use one runway at a time. As reported by the local San Francisco Chronicle from the airport duty manager, “Flights coming in and out of SFO are experiencing delays of an hour to 90 minutes as of 11 a.m.”

The traveler experiences today could be much better or worse than that 60-90 minutes. Sometimes it’s luck, but more often it’s where the flight is coming or going from, and possibly even the plane’s size.

International flights have been largely unaffected; a nonstop to Paris left right on time at 2:45 p.m. Flights to and from Asia were on time or early. Only a flight to London was 30 minutes late.

But with domestic flights, there’s been a wide variety. For examples, flight 397, one of United Airlines’ “P.S.” (Premium Service) flights from JFK to SFO, due in at 11:47 a.m. arrived eight minutes early at 11:39 a.m. And, flight 760, the same sort of flight back to JFK, left 3 minutes EARLIER than its scheduled departure time of 10:40 a.m.

Even much maligned and often delayed flights to and from Newark did okay. The flight scheduled to arrive at 11:55 a.m. was in 17 minutes early, and the 10:47 a.m. flight was only 12 minutes late.

Now let’s take a look at the shorter flights, for example, to and from Los Angeles (where the weather is good). Flight 318, scheduled to arrive at 10:58 a.m., was about an hour late. Flight 864, scheduled to arrive at 11:42 a.m., pulled in at 3:37 p.m., almost 4 HOURS late. And, many other flights are two hours late or more. Beyond the weather, these planes often go back and forth between San Francisco and Los Angeles, or are used for other short flights, so the delays get worse throughout the day.

Next, I took a look at SFO to Las Vegas flights. While flights are arriving about an hour late, the 5:30 p.m. flight on a 50-seat United Express plane has been canceled with the reason of “Air Traffic Control.” (Translation: we can’t get all the flights in with reduced landing slots, so let’s cancel one that affects a smaller number of people.)

To and from Seattle? Again, big jets are within an hour of on time, one United Express flight has been canceled, another is four hours late.

For little flights around California with only regional jets and propeller planes, driving might be a better alternative. San Francisco – Santa Barbara flights range from about 100 minutes to three-plus hours late. San Francisco to Sacramento is about the same.

Now, the point of this post is not to castigate United Airlines today. They are doing the best they can with their schedule and poor conditions (although there might be a side issue of whether or not the schedule is realistic given SFO’s record for delays).

But for the traveler, it does illustrate some important lessons for booking flights. Here are five tips in a nutshell:

1. When possible take a nonstop.

2. Given a choice, take a larger plane, and definitely a full-sized plane over a commuter plane.

3. With a connection, two longer flights have a better chance of being on time than a short flight and a long flight, since they are more likely to be a priority for the airline.

4. For international flights, try to take the long flight first. (Anyone going to Europe today from San Francisco with a connection in, say, Frankfurt, should be fine. Travelers through JFK or Newark may be okay. Anyone connecting in Los Angeles is likely out of luck.)

5. Finally, and perhaps most important, do NOT rely on a blanket statement of delays at an airport. An average means nothing for a specific flight. One of the only things worse than a flight delay is showing up at an airport expecting a delay and finding the flight has already left.