More than 1,000 flights were scrapped across the US on Monday after an FAA communications system failure grounded traffic across the Northeast — and the fallout could stretch into a second day.

The trouble started with an outage at a critical FAA facility in Philadelphia. Then it got worse: a rail worker accidentally severed a fiber line that carries telecommunications for the nation's air traffic systems, according to Transportation Secretary Sean Duffy. The line was repaired by early evening, but airlines warned that residual delays and cancellations would keep piling up as they repositioned planes and crews.

Newark Liberty International Airport took the brunt of it — more than half of its scheduled departures were canceled. Philadelphia International wasn't far behind, losing roughly a fifth of departures. At one point the FAA had issued ground stops at all three major New York-area airports plus Boston Logan, leaving travelers stranded in terminals, planes idling on taxiways, and some flights diverting to other cities entirely.

United Airlines, which runs a big hub at Newark, was hit hardest of any carrier, with more than 350 cancellations by Monday evening. Most major US airlines issued travel waivers covering Newark and Philadelphia, letting affected passengers rebook, reschedule, or fly from a different nearby airport without change fees.

Know your refund rights

Here's the key thing many travelers miss: even though an air traffic control failure isn't the airline's fault, US Department of Transportation refund rules still apply. If your flight is canceled or significantly delayed — for any reason — and you decide not to travel, you're entitled to a refund of your ticket. That's handy whether you'd rather take the train, drive, or grab a backup flight on a competing airline and ditch the original booking.

Skip the queue, use the app

Standing in a rebooking line at a packed airport is the slowest way to fix a canceled trip. Instead, download your airline's app beforehand and attach your trip details. Most carriers let you rebook yourself in a few taps, which is far faster than waiting for an agent or sitting on hold.

What about hotels and meals?

Don't expect the airline to pick up the tab for a hotel or dinner when the problem is air traffic control — carriers generally don't cover those costs in this scenario. But if you booked your flight with a credit card that includes travel insurance, you may be able to claim some expenses back. Keep every receipt and check your card's policy details before filing.

Why it matters

Outages like this are a reminder to build slack into any Northeast flight itinerary: book morning departures when possible, know your refund rights before you need them, and have the airline app set up before you fly. If you're booked through Newark or Philadelphia in the coming days, check your flight status and any active travel waiver before heading to the airport — the ripple effects from this outage won't clear immediately.