Canada wildfire smoke again disrupts flights in the Eastern U.S.

KEY POINTS

• The FAA warned it could slow inbound flights to New York City; Philadelphia; Charlotte, North Carolina; and Washington, D.C.
• Heavy smoke from wildfires in Canada was cutting visibility.
• More than 4,200 U.S. flights were delayed Thursday, according to FlightAware.

A Delta Airbus A320 airplane takes off from Ronald Reagan Washington National Airport in Arlington, Virginia, as smoke from wildfires in Canada blankets the area.

Saul Loeb | AFP | Getty Images

Smoke from Canada wildfires disrupted flights in the Eastern U.S. again Thursday after hundreds were delayed a day earlier due to decreased visibility, the Federal Aviation Administration said.

"The FAA will likely need to take steps to manage the flow of traffic safely into New York City, [Washington] DC,  Philadelphia and Charlotte [North Carolina] due to reduced visibility from wildfire smoke," the agency said.

The FAA briefly halted inbound traffic to Philadelphia International Airport earlier Thursday.

Hundreds of flights to and from LaGuardia Airport in New York and nearby Newark Liberty International Airport were delayed Wednesday due to the heavy smoke. The FAA had briefly paused traffic altogether into LaGuardia during the day.

By Thursday evening, more than 4,200 flights to, from and within the the U.S. were delayed, according to flight tracker FlightAware.

More than 280 LaGuardia-bound flights, almost half of the day's schedule were delayed as of 6:40 p.m. ET Thursday, while another 161 departures were delayed, FlightAware's tally showed.

At Newark, 129 departures were delayed, or 19% of the schedule, and 143 flights headed for the New Jersey airport were delayed, around a fifth of the total.

American Airlines and United Airlines said they were waiving change fees and fare differences for travelers affected by the air quality issues in the region if they can fly before next Wednesday.