It's a busy time to travel. Go to the airport prepared.
Don't fly at night, on Fridays or from Philadelphia if you want the best chance of taking off on time or picking up a passenger on schedule.
These are among the simplest conclusions of a Sun analysis of a year's worth of domestic departures from Baltimore-Washington International Thurgood Marshall and three other airports in the region.
Travel is on many Americans' minds, with 42 million people expected to fly on U.S. airlines around Christmas and New Year's. Holidays, like the weather, can play havoc with the rules of thumb -- but flying early is still the best advice.
"Throughout the day, it gets worse," said Darryl Jenkins, an airline analyst from Northern Virginia. "You'd never, ever want to book a last flight out."
About 21 percent of departures from BWI and Washington Dulles International were delayed, according to The Sun's review of Bureau of Transportation Statistics data for the year ending in September. That was slightly more often than the national average of 19 percent. Ronald Reagan Washington National had the region's fewest delays at 14 percent; Philadelphia International had the most at 25 percent.
Philadelphia has troubles because it is in the middle of the Northeast's crowded airspace, an airport spokesman said. Aviation analysts explained other Sun findings this way: Early-morning flights, before 8 a.m., had little to delay them. The domino effect of delays throughout the day made flights after 7 p.m. the worst. The intersection of business and leisure travelers slowed departures on Thursdays and Fridays the most, leaving unpopular Tuesday and Wednesday as the best days on average among the four airports.
The carrier seemed to make a difference, too. With more time on the ground between flights, the traditional airlines had the best records -- markedly better than their regional partners flying the feeder planes to their hubs.
Discounter Southwest Airlines had significant delays at BWI and at its other major airports because it does not use the feeder-plane plan. Southwest flies a packed schedule directly from city to city, making it harder to recover from an early delay.
When things go wrong, planes can "make up time in the air" by using more fuel to fly faster or by catching tailwinds -- something Southwest has proved to be particularly good at. On typical airlines, a flight that leaves late usually also arrives late.
A departure is counted as delayed when it backs away from the gate 15 minutes or more after the scheduled time. Airlines pad schedules to account for congestion, though they keep that to a minimum to squeeze work from the planes.
Most people know December is a busy travel month. But it isn't the worst time to fly. That's the early summer. Jenkins said that if you really hate delays, avoid flying in June and July, when thunderstorms and lots of travelers make for a bad mix.
Discount fares have enticed more people to fly in recent years and are helping to overwhelm the air traffic system, industry analysts say. The share of delayed departures has increased by a third since 1995 nationally. The change was even worse at the region's airports.
In addition to extra flights, airports face new security restrictions in light of the 2001 attacks. One of the most delayed days for flying in the past year at area airports was Aug. 10, when British authorities said they thwarted a bomb plot and U.S. officials restricted liquids on carry-on baggage.
The Federal Aviation Administration said the East Coast is a particular challenge because of its busy airports and crowded air space. Domestic flights compete frequently for space with international ones on the ground and air.
The FAA is working on several measures to improve the problem, including air traffic technology to enable pilots to fly more direct routes, agency spokeswoman Laura Brown said.