Incidents of disruptive airline passengers are growing.Since August 2011, police have responded to approximately 200 calls of disturbances on aircraft at Denver International Airport, said airport spokeswoman Laura Coale.The latest incident happened on Sunday night when a New York-to-Los Angeles JetBlue flight was diverted to DIA after a male passenger groped a woman, told a flight attendant to get away from him and was seen downing several unidentified pills, authorities said."We just can't tolerate that, because we just don't know much it's going to escalate," the JetBlue flight pilot can be heard saying on a passenger video.Marcus Covington was arrested on suspicion of interference with a flight crew when the plane landed at DIA on Monday morning, said John Walsh, U.S. attorney for the district of Colorado. If convicted, Covington could face up to 20 years in prison.7NEWS checked into the frequency of these incidents.In 2011, the Transportation Security Administration reported more than 1,218 incidents involving unruly passengers nationwide.While those numbers have fluctuated over the years, the International Air Transport Association reported a 29 percent jump in disruptive passenger incidents worldwide between 2009 and 2010.Alcohol often fuels these incidents."A flight attendant can realize when somebody's had too much to drink (during a flight). But what they don't know is how much did they have to drink before they even got on the plane," said Jeff Price of Metro State's aviation department.DIA deals with these cases regularly.That includes a case in 2010, when a United flight was diverted here after a passenger tried to open a jetliner door in the air."This is not happening on our flight. You know. You think, just like the movie," said one passenger after the flight eventually landed in Las Vegas.It's a storyline we'll likely see again, because of DIA's central location in the United States."We're right in the middle of the country. So if there's a problem on an aircraft between point A and point B, we're right in the middle," said Price.Industry observers are also concerned about cases involving unruly crew members. Long hours and low pay often contribute to these outbursts, said Price.