For a second day in a row, the US Federal Aviation Administration has issued a ground stop for flights bound for New York's LaGuardia airport as smoke from Canadian wildfires continues to spread across the northeastern United States.

The FAA cited reports of low visibility for the ground stop, which is set to last until 7:45 am ET and could be extended. A similar ground stop was issued Wednesday.

The FAA's operations plan for Thursday shows smoke potentially impacting travel from New York to Charlotte. It lists New York's three major airports, Philadelphia, the three Washington airports and Charlotte as all having the possibility of a ground stop or delay program similar to what took place on Wednesday.

US airlines have delayed 472 flights Thursday morning and canceled 55 of them according to FlightAware. New York's JFK airport and Newark Liberty Airport in Newark, New Jersey, were the hardest hit by the haze, with 27 delays and 13 delays respectively.

US Secretary of Transportation Pete Buttigieg tweeted Wednesday that, "Smoke from Canada's wildfires is affecting visibility in our airspace and leading to delays. The FAA is fully prepared to modify operations as needed."

This is a developing story and will be updated.