Frontier Airlines Chicago Flight Diversion Sparks Wild Conspiracy Theories After Pilot's Unusual Announcement. A routine Frontier Airlines flight from Denver to Chicago made an unexpected diversion to Milwaukee last night, triggering a frenzy of speculation online. Passengers claim the pilot said they were avoiding "unexplained airspace activity," leading some to believe it was a drone incursion. However, the airline later clarified the diversion was due to a minor mechanical issue, with no threat to safety. Despite this, viral videos of passengers filming the sky have fueled claims of a cover-up. Real or fake? The official explanation is real, but the conspiracy theories are entirely fake.