Holiday travel across the United States is turning into a mess.

Powerful winter storms are causing major problems as people try to get home after Christmas. Airports are crowded. Flights are delayed. Many trips are canceled altogether.

According to flight tracking data, 1,371 flights within, into, or out of the US were canceled on Friday. Another 4,485 flights were delayed across the country. Globally, the numbers are even higher. Airlines canceled 1,690 flights and delayed more than 20,000 worldwide.

New York City has been hit especially hard. LaGuardia, JFK, and Newark airports are all dealing with severe weather. Forecasts say up to 9 inches of snow could fall in the area. That has slowed operations and caused long lines and missed connections.

The trouble is not limited to New York. Airports in Detroit, Philadelphia, and Boston are also seeing heavy delays and cancellations.

Weather conditions are making travel dangerous in many regions. The Great Lakes area is dealing with ice buildup. Roads are slick. Flights are struggling to stay on schedule.

JetBlue and Delta have been hit the hardest so far. By 2:00 p.m. Eastern Time, JetBlue had canceled 225 flights. Delta followed closely with 212 cancellations.

All of this is happening during one of the busiest travel times of the year. Millions of Americans are trying to return home after spending Christmas with family.