Heavy fog made for a slow Sunday for many travelers at Boston Logan International Airport.
According to global aviation data service FlightAware, more than 400 flights were delayed and at least 86 were canceled as of 10:30 p.m. Of those delayed, 248 flights were destined for Boston (36 percent of scheduled arriving flights), and 169 were flying out of Boston (25 percent of scheduled departing flights).
The Federal Aviation Administration site said low cloud ceilings in the area were the source of the backup, which averaged 3½ hours at 9 p.m.
Massport spokeswoman Jennifer Mehigan said inclement weather in other parts of the country also contributed to the backlog.
Correction: Because of a reporting error, an earlier version of this story misidentified a Massport spokeswoman.Abigail Feldman can be reached at email@example.com.