Airlines prep for holiday crush: More flights, bigger planes

DALLAS (AP) — Airlines are shifting the timing of thousands of flights, even adding dozens of red-eyes, as they try to avoid delays while hauling millions of passengers from now through the Christmas weekend.

Success or failure could all depend on the weather and Mother Nature isn't making it easy on airlines.

Rain and fog in the Northeast caused nearly 200 flight delays Wednesday morning in Boston, New York and Washington – the busiest part of the country's airspace. Rain in Chicago and Atlanta caused some delays in those cities too. Severe storms that ripped through Mississippi and Alabama, however, had little impact on air travel since no major airports are in those states.

There were about 600 delays and 16 cancellations by noon, according to flight tracking site FlightAware. More than 21,000 flights were scheduled for today and a typical day sees about 150 cancellations and 4,000 delays.

The catch: flights are extremely full over the holiday period, with most travelers unable to make changes in their schedule.

Airlines expect about 38 million passengers over a 17-day period spanning Christmas and New Year's, an increase of about 3 percent, according to an industry trade group, Airlines for America. The group says the average flight could be 90 percent full.

Crowds like that mean that any hiccup in the system — delays at a major airport, a technology glitch — can ripple across the country and leave tens of thousands of passengers standing in airport lines.