We all know that some flights are more prone to delays than others. But some trips just seem destined for failure.
Take American Eagle flight 3637 from Miami to Charlotte, North Carolina. Passengers on that flight in April did not arrive on time once. That's right, every single day of the month the 1 hour, 55 minute flight was late. The average delay: an hour and 2 minutes.
And that was just the average delay.
On May 31, for example, the plane got in at 9:40 p.m. -- three hours behind schedule.
American Eagle 3637 was the worst offender, according to an analysis of Department of Transportation statistics, but it certainly wasn't alone in its tardiness.
Southwest flight 1602 from Phoenix to Denver averaged delays of 42 minutes during April. Only five times during the month did the flight arrive on-time.
For passengers flying today, there are plenty of hassles, from taking shoes off at security to fighting for overhead bin space. But ultimately the goal is to get people safely to their destination -- hopefully, on time.
With fewer planes in the sky than there have been in years, overall on-time performance is improving. The 18 airlines that report statistics to the federal government were on time 85.3 percent of the time in April, compared with a rate of 79.1 percent a year earlier and 80 percent in March, according to the Bureau of Transportation Statistics.
Yet a handful of flights remained nightmares for travelers. Anybody who booked a ticket on one of these trips was almost certainly guaranteed a late arrival.
"These systemic delays are a logistical nightmare for airlines. They have a finite number of planes, pilots, gates, and if they end up in a situation when they've overextended themselves and can't operate it on time, there are limited options to fix it without a significant schedule change," said Daniel Baker, chief executive officer of the flight-tracking site FlightAware.com. "Given the challenges that airlines are facing and the need to operate tight schedules in order to hopefully achieve their thin profit margins, these kind of problems aren't going away overnight."
There are plenty of things that savvy travelers can do to avoid these problematic flights. The first is to check historic on-time performance. The Bureau of Transportation Statistics offers a database of airline on-time statistics which allows people to search by specific flight numbers.
Travelers can also make some smart picks. First, try to fly non-stop, advises Rick Seaney, CEO of airfare-search site FareCompare.com and an ABCNews.com columnist. However, avoiding a connection can add significantly to ticket prices, sometimes as much as tripling them, Seaney said. If connecting, think about the weather in that city. In winter, it might be worth adding an hour to your trip to fly through a warm-weather city. In summer, try to avoid airports that are prone to thunderstorm delays.
The DOT soon will require airline to post on-time statistics when people book tickets (though the airlines are seeking an extension). A flight is considered late if it arrives 15 minutes or more past the scheduled time of arrival.
"I think airlines' feet are going to be held to the fire when they actually do put the required delay times on flights before purchase and just like tarmac delay fines they will work around the biggest issues first," Seaney said.
"Travelers do need to realize that early-morning flights always have better chances of on-time operations," said Bill Miller of travel site CheapOair.com.
An ABC News analysis of the Bureau of Transportation delay information shows that six of the 10 most-delayed flights all either started or ended in Miami. All were operated by American Eagle, a regional airline owned by American Airlines.
"We are striving to overcome those challenges and make more improvements for an even better performance going forward," said American Airlines spokeswoman Andrea Huguely. "Yes, we have had a few challenges in relation to our Miami hub lately, several related to dealing with construction issues at the airport. We have formed employee teams to help us do better in our handling of these issues."
American Eagle had the lowest overall on-time performance of any airline at 82.3 percent, but Huguely said that's an improvement over the 73.8 percent the airline has averaged in the past four years.
"Those figures reflect significant improvement that we've made," she said.
Southwest Airlines had the other four worst-delayed flights in the top ten.
At Southwest, the delays have a different cause: the airline is holding specific flights for connecting passengers.
Steve Hozdulick, who is in charge of the airline's on-time performance program, said the Southwest flights were late because the airline wanted to ensure people made end-of-the-day connections.
Flight 1602 from Phoenix to Denver is scheduled to leave at 7:45 p.m. and has a lot of passengers connecting from other airports. Hozdulick said that plane is often held to make sure people make their connections.
"We really try to deliver the customer to their destination that day," he said. "We don't want to have them inconvenienced by missing their connection and having to wait potentially overnight. So especially later in the day we really try to make the customer connection if it's at all possible."
With airlines selling a higher and higher percentage of their seats, it leaves very little room in the system to accommodate passengers who miss their initial flights.
Fixing the system isn't that easy. If the schedule is changes to solve one problem, another one often arises.
"Sometimes it's a little bit of a whack-a-mole," Hozdulick said. "We try to continually address those consistently poor-performing flights we have."
The top 10 worst-delayed flights in April, according to the Bureau of Transportation Statistics, are:
#1: American Eagle flight 3637 from Miami to Charlotte; late 100 percent of the time; average delay: 62 minutes.
#2: American Eagle flight 3626 from Pensacola, Florida, to Miami; late 84 percent of the time; average delay: 24 minutes.
#3: Southwest flight 1602 from Phoenix to Denver; late 80.8 percent of the timel average delay: 42 minutes.
#4: American Eagle flight 3648 from Cincinnati to Miami; late 80 percent of the time; average delay: 54 minutes.
#5: American Eagle flight 3638 from Charlotte to Miami; late 80 percent of the time; average delay 43 minutes.
#6: Southwest flight 159 from Houston to Austin; late 77.3 percent of the time; average delay: 28 minutes.
#7: Southwest flight 35 from Houston to New Orleans; late 76.9 percent of the time; average delay: 33 minutes.
#8: American Eagle flight 3619 from Miami to Tallahassee, Florida; late 76 percent of the time; average delay: 33 minutes.
#9: American Eagle flight 3661 from Miami to Indianapolis; late 76 percent of the time; average delay 44 minutes.
#10: Southwest flight 712 from Houston to St. Louis; late 73.1 percent of the time; average delay: 31 minutes.