Mexico has temporarily grounded Aviacsa airline after officials reported irregularities in the maintenance of 25 planes.
The Transportation and Communications Department said the low-cost airline has 60 days to fix the problems.
The action Tuesday effectively shut operations at the airline, which says it has a fleet of 26 planes serving 17 Mexican cities and Las Vegas.
The department said the problems put passengers at risk, but Aviacsa issued a statement denying any safety problems.
Haydee Cordova, Aviacsa's assistant director for legal affairs, said Wednesday the problems were cosmetic - opaque logos, dull lights and scratches on the wings - and that they had already been corrected on five of the planes.
Cordova said Aviacsa officials have asked the Mexican government for another inspection.
In the meantime, the airline will validate passengers' tickets for future flights, she said.