Here’s Why It Could Take Days for Flights to Return to Normal

The near-total shutdown of the nation’s airspace ended on Friday evening, but its ripple effects continued into Saturday as airlines canceled thousands of flights.

By Saturday morning, almost 15 percent of the day’s flights had been scrapped, and the number was still climbing. The recovery will most likely last for days as airlines work to juggle their schedules, rebook passengers and reposition planes.

Aviation functions like a relay race. To work well, many things have to align in the same place at the same time, including the availability of planes, crews and an open airport gate.

On Friday, thousands of planes were pulled from the air, filling up limited space on the ground. Many returned to the airports they had just left, according to Cirium, an aviation data firm. Jets at crowded airports weren’t allowed to depart and sat idle while flight crews quickly hit their legal working limits.

Pilots are generally limited to eight or nine hours of flying and a total shift length of 9 to 14 hours, though union contracts and airline policies often shrink those windows. Flight attendants are also governed by limits on the length of their shift. Both must receive lengthy breaks in between shifts, too.

For instance, a pilot who was scheduled to fly from New York to Miami on Friday night could easily have timed out while waiting for the ground stop to end. That would have left the airline struggling to find replacement pilots not only for the flight from New York, but also for the flight that pilot was scheduled to operate out of Miami on Saturday. Multiply that by hundreds and airline schedules can quickly implode.

Take N865DN, the tail number for a Boeing 737 operated by Delta Air Lines. It started Friday flying from Charleston, S.C., to Atlanta. From there, it made round trip flights to Louisville, Ky., and Norfolk, Va., returning to Atlanta, according to Flightradar24, a flight-tracking service.

The plane was supposed to fly on to Savannah, Ga., back to Atlanta, and then to Chicago, where it would start the day on Saturday. But it never made those last three flights.

Delta rebuilt its Saturday plan, with the plane scheduled to fly from Atlanta to Spokane, Wash., and on to Salt Lake City and Raleigh-Durham, N.C.

For minor disruptions, airlines can play catch-up by restarting flights and trying to make up for lost time. But bigger disruptions, such as the one that occurred Friday, often require resetting the network by proactively canceling many flights.