The storm and cold weather of the last week will cost the nation's airlines as much as $100 million in lost revenue and increased costs, according to an estimate from a leading airline analyst.

Helane Becker, airline analyst with Cowen and Co., said the weather would cost U.S. airlines between $50 million and $100 million in an estimate released Wednesday. Becker said the weather caused about 20,000 flights cancellations nationwide, which she said is 5,000 more flights than were canceled in due to Superstorm Sandy in 2012.

Becker does not break down the cost per airline, but she noted that JetBlue Airways (JBLU) was hit particularly hard by the storm. The New York-based airline had to virtually halt operations at those airports Monday afternoon into Tuesday after delays in the previous three days caused the airline to run out of pilots able to fly under new FAA rules requiring addition rest for pilots.

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"Going forward we believe the airlines will adopt a more conservative approach during storms," she said. "In the past, they might take a delay; going forward they will outright cancel."