New York CNN  — 

Airlines are still digging themselves out from an intense day of storms that battered the eastern half of the United States on Friday and saw every state under some type of weather-related alert.

As of early Saturday evening, more than 1,200 flights across the country were canceled, and 4,700 flights were delayed, according to data from tracking site FlightAware. While that’s a significant improvement from Friday’s nearly 2,300 cancellations and 9,000 delays, airports across the Midwest and Northeast continue to experience major travel delays.

In Michigan, where more than 140,000 customers are currently without power, Detroit’s Metropolitan Wayne County Airport has delayed 40% of its outgoing flights. Buffalo Niagara International Airport in New York has canceled 60% of its flights. Airports in Chicago, Denver and Boston are also experiencing holdups. Nearly 550 flights going in and out of Chicago’s O’Hare International Airport have been postponed. Denver International Airport, where temperatures Saturday evening dropped to zero, had the second-largest number of cancellations.

These travel delays are exacerbating an already-difficult week for airlines and their passengers. Last week, more than 200 United and Alaska Airlines flights were canceled each day due to the federally mandated grounding of Boeing 737 Max 9 aircraft. The Federal Aviation Administration instated the order after a piece of the fuselage blew off a 177-person Alaska Airlines flight on January 5. The incident left a gaping hole in the side of the plane and ripped headrests off seats as the plane flew at 16,000 feet shortly after taking off from Portland, Oregon.

United and Alaska Airlines, the two largest US carriers that use the Max 9 aircraft, are among the airlines canceling the most flights, according to FlightAware. United topped the list Saturday with nearly 250 canceled flights, nearly 10% of its fleet. Alaska Airlines experienced the fourth-highest number of cancellations, with almost 120 flights called off.

Both airlines said last week that they have canceled all flights on their Max 9 planes until mid-January.