EXPLAINER: Why was holiday-season flying such a nightmare?

A forecast of better weather means that the worst may finally be over for tens of thousands of air travelers who were grounded by flight cancellations that skyrocketed over the New Year's Day weekend.

January usually means fewer people flying, and that will be even more true in 2022 because many business travelers haven't returned to the skies.

The lighter crowds should buy airlines time to prepare for the next big onslaught, around spring break. That, however, won't help the hundreds of thousands of flyers whose Christmas and New Year's plans were scrambled by airline staffing shortages and wintry weather.

Here’s a look at the factors that snarled flights for so many people during holiday season, and what the next few weeks are likely to bring.

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WHAT HAPPENED?

Airlines were prohibited from furloughing employees as a condition of receiving $54 billion in federal pandemic aid from taxpayers. But that didn't stop them from encouraging tens of thousands of workers to quit or take long-term leaves of absence after the pandemic torpedoed travel in 2020.

Airlines that got caught with shortages of pilots, flight attendants and other workers last summer and fall — think Southwest, American, Spirit and Allegiant — thought they had time to beef up for the winter holidays. They went on hiring sprees.

That wasn't enough, though, when the highly contagious omicron variant of COVID-19 struck, knocking out flight crews just as holiday crowds began to pack airports. United and Delta were among the first to get hit just before Christmas, blaming canceled flights on a lack of crew members because of the surging virus.

Then storms packing snow and high winds lashed the Pacific Northwest, the Rockies, the Midwest and finally the mid-Atlantic region, creating waves of cancellations...