Mexico City - Mexico is trying to crack down on airline fees and flight delays. The carriers are having none of it.

Mexico's consumer-protection agency fined five airlines including New York-based JetBlue a combined 22.4 million pesos ($1.27 million) for alleged transgressions such as charging fliers for their first checked bag. The entity, not known for taking on major corporations, is also monitoring whether airlines comply with a new requirement to compensate passengers when flights have major delays.

The question is whether Profeco, as the regulator is known, can make the fines stick - and defeat a legal challenge by the airlines in Mexican courts. The carriers are still charging for luggage on flights to the U.S. and Canada, saying an international treaty supersedes the new laws. That makes Mexico City the latest front in the clash between passengers' rights and airline fees.

"This case is pitting the airlines' economic freedom to do business against a large part of the population that uses these services," said Julio Salazar, the legal director at Power to the Consumer, an advocacy organization that supports the effort to restrict the fees.

At the heart of the matter is whether the Mexican constitution recognizes consumer rights as human rights, as some scholars have interpreted. The foreign treaty says airlines are free to set their own pricing models according to market principles. The conflict means the case has the potential to reach Mexico's Supreme Court, Salazar said.

"This will come down to Profeco's capability to litigate before the courts," he said. Settling the dispute could take more than a year, he added.