JetBlue Airways has stopped all scheduled flights to and from New York and Boston, and Southwest has ground to a halt in Chicago as airlines deal with a blast of freezing temperatures that has caused massive cancellations and delays.

JetBlue plans to resume some flights in the Northeast on Tuesday morning and return to full operation at four affected airports by mid-afternoon. It says the timeout would let crews rest and give mechanics a chance to service planes.

Southwest Airlines Co. suspended flights at Chicago's Midway Airport around midday and canceled more than 100 of its planned 230 daily departures there.

Spokesman Brad Hawkins says Southwest hopes to reopen at Midway by Monday evening.