Travelers with flights out of Denver International Airport (DIA) to Puerto Vallarta and Guadalajara found themselves searching for other plans after airlines canceled flights following widespread cartel violence across Mexico on Sunday.Mexico's Ministry of Defense said Mexican Special Forces carried out an operation in Jalisco on Sunday, killing Nemesio Rubn Oseguera Cervantes, also known as "El Mencho," the leader of the Jalisco New Generation Cartel (CJNG).The killing of the cartel's leader triggered retaliatory cartel attacks that blocked roads across western Mexico and prompted civilians and tourists to be ordered to shelter inside. One Puerto Vallarta resident, who is orginally from Pueblo, sent Denver7 a video of the scene outside his home on Sunday, which shows smoking and burnt cars along the streets. In the video player below, you can watch Maggie's report as she listens to how passengers were impacted at DIA. Travelers deplaned from Denver flight to Mexico amid cartel violenceUnited Airlines said all of its flights from DIA to Puerto Vallarta and Guadalajara were canceled on Sunday, while Southwest Airlines said it canceled the four flights scheduled to Puerto Vallarta and four returning flights.John Harrington and his family, who live in Montana, were on their way to join friends already vacationing in Puerto Vallarta when their connecting flight from DIA was deplaned around 9:30 a.m. on Sunday."We rented a house with some friends, another family with some kids in Punta Mita, just north of Puerto Vallarta. So the plan was just to fly into Puerto Vallarta and take a 30 or 40 minute car ride north and just stay in a in a beach house with friends and spend the week there," said Harrington. "When we boarded the plane this morning in Denver, our friends called us and mentioned that there was some unrest outside of their hotel in Puerto Vallarta itself, and they said that there appeared to be some car fires and some cartel activity."Harrington's friends sent him videos of Puerto Vallarta from their hotel, which they had been locked down in after violence erupted.Harrington said as he, his wife, and two young kids got settled in their seats on the plane, the pilot notified passengers about security risks in Puerto Vallarta."I think everyone was pretty surprised and a little confused," said Harrington. "We're just glad that we're all safe and out and wishing the best for everybody who is in the state of Jalisco and Puerto Vallarta."Denver-based national security consultant Sam Scanlon said CJNG is not just a street gang, but instead one of the most powerful cartels in Mexico."This is a paramilitary force that has armored vehicles, it has rocket launchers, it has drones. Not only do they traffic drugs like cocaine and heroin, but they also do synthetics like fentanyl," said Scanlon. "They're in the avocado business, lumber fishing, they steal fuel from Central America and other parts of the world as part of another revenue stream."The Embassy of Mexico in the U.S. says American authorities provided intelligence to Mexican Special Forces for the operation that killed the cartel leader."That could mean a wide range of things. The U.S. government has been operating in Mexico and Central America, of course, now for decades, and we have different assets from from informants to satellites," said Scanlon. "This was sending a real message, not only from the United States, but also from Mexico."He said while there is no indication cartel members are targeting Americans in Mexico, travelers with plans to go to cities like Puerto Vallarta and Guadalajara in the near future should be cautious."That's one thing with the cartels, is they're really smart in the way they go about things. They know that if they target U.S. citizens and they kidnap U.S. citizens, then that gives the permission structure for the U.S. government to bring its full force," Scanlon said. "My recommendation for any U.S. citizen traveling down there is to really consider it if it's worth it or not, because this situation right now is very dangerous. It's escalating right now as we speak." ...read more read less