At least six U.S. airlines cancelled dozens of flights into and out of Mexico City and Toluca airports Thursday after the Mexican volcano, Popocatepetl, began rumbling and spewing ash, reports BBC News.
Popocatepetl has been rumbling all year, but only started spewing steam and ash earlier this week. Airport authorities, however, insisted that there was no danger. By Thursday afternoon no ash from the volcano, which is about 40 miles away, had reached the airport.
"There is a very thin presence of ash, which does not harm operations or affect equipment," an unnamed airport spokesman said.
U.S. Airways, Delta, United, American and Alaska Airlines cancelled flights on Thursday as a precaution, but resumed their normal schedules on Friday.
"We are closely monitoring the situation in Mexico City as volcanic ash continues to be emitted from Popocatepetl," said American Airlines spokesman Matt Miller.
Cities affected by the cancellations included Houston, Dallas, Denver, Phoenix, Chicago and Los Angeles.
The alert level for Popocatepetl has been set just under the evacuation level, but officials say there are no immediate plans to evacuate just yet.