It’s no joke: Many of the worst flights in the U.S. either take off or land in Newark.

Flight delays are piling up at this often-maligned New Jersey city. Of the 100 most-delayed flights over the past year, 40 come and go from Newark, a key gateway to New York City, according to data compiled for The Wall Street Journal by the Bureau of Transportation Statistics.

The two most chronically delayed flights, according to BTS, are both Delta Air Linesdepartures from Newark to Atlanta, one at 5 p.m. and the other at 6:25 p.m. In other words, rush hour.

Flight 2743, the 5 p.m. departure to Atlanta, ranked worst for the 12 months through May. It has plenty of padding in its schedule—Delta times the 745-mile trip to Atlanta for two hours, 43 minutes—30 minutes longer than the airline’s 10:30 a.m. flight from Newark to Atlanta, and about an hour longer than the typical flying time of one hour, 40 minutes in the air.

But the extra time isn’t enough. Flight 2743 was 30 minutes late or more on six of every 10 trips. And when it was late, it was reallylate, averaging a whopping 83-minute delay. The 6 p.m. departure, Flight 2843, ran late on half its trips. The average delay was 79 minutes.

Much of the bottleneck is in Washington, D.C. Both flights out of Newark have to fly through heavily congested airspace in the Washington area, Delta says, where much of the traffic headed into and out of the Northeast meshes together, creating a choke point for the nation’s air travel. One flight, Delta 2843, also suffered because the airplane used on that trip comes to Newark from Atlanta in the late afternoon, and it runs chronically late.

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