New York CNN Business  — 

US airlines canceled thousands more flights Thursday as a powerful winter storm packing ice, rain, sleet and several inches of snow is stretching from the Midwest to the South and eventually parts of the Northeast.

On Thursday, there were more than 4,200 cancellations within, into, or out of the United States, according to flight tracking site FlightAware. There were nearly 600 flight delays as of Thursday morning.

The most impacted airports are in Texas. Dallas-Fort Worth, an American Airlines hub, has canceled 548 flights, or 57% of its schedule. Austin-Bergstrom has canceled 76% of its schedule, amounting to 216 flights. Dallas Love Field, a Southwest hub, has axed 85% of its schedule.

Across the Midwest, St. Louis, Indianapolis, Columbus, Cincinnati and Cleveland all have sizable disruptions to their schedules too.

Southwest Airlines (LUV) has canceled 28% of its schedule, or about 1,000 flights. That’s followed by American Airlines (AAL), with 19% of its Thursday schedule eliminated and United Airlines has nixed 200 flights, 11% of its schedule. Feeder airlines for the major carriers are also clipping schedules, including Envoy Air (60% of its schedule is canceled), Republic Airways (29%) and SkyWest (13%).

Airlines issue travel waivers letting flyers rebook for free when severe weather impacts operations. CNN Travel offers a guide on what to do if your flight is affected.

The storm system’s reach is so expansive that more than 100 million people across at least 25 states were under winter weather alerts as of early Thursday, from the Mexican border to New England. And some areas, including Texas, are expected to feel the impacts through Saturday afternoon.

Heavy snow began falling Tuesday and more than 20 inches had piled up in the Colorado Springs area, according to the National Weather Service. Parts of Illinois were inundated with more than a foot of snow, while Indiana had tallied more than 11 inches. That caused more than 2,300 flight cancellations across the US.

It’s been a miserable few weeks to be an airline traveler, especially after last weekend’s storm that complicated service. Winter weather and Omicron surges left 20,000 US flights canceled over the busy holiday travel season. As demand picked up, staffing cuts also left airlines with fewer employees than they had before the pandemic.