Delta, American Airlines and Alaska Airlines canceled a dozen flights scheduled to depart the Mexican capital, while Spirit Airlines canceled flights to and from Dallas and Fort Lauderdale, Fla., CNN reported.
Mexican airlines were operating on schedule.
The Mexican government's National Center of Disaster Prevention said Popocatepetl has expelled nearly 100 bursts of ash, gas and steam over the last 24 hours, and officials said they recorded 12 hours of medium- and high-frequency tremors at the volcano 50 miles from Mexico City.
Airport officials said on Twitter the ashes hadn't yet reached Mexico City International Airport.
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