It turns out the mysterious case of the jetpack guy casually flying around at a few thousand feet above the ground in California could actually be something completely different, albeit just as dangerous. According to documents collected by The Black Vault (via The Drive) through the Freedom of Information Act, an American Airlines pilot who made the jetpack sighting reported to the FBI that "what he saw was exactly like the drone in the YouTube video below."
As you can see, the video depicts a radio-controlled drone with two propellers attached to a backpack that's fitted to a mannequin. The dummy seen here, resplendent in a full camouflage jumpsuit and boots, isn't necessarily the same one that may be buzzing commercial flights in Los Angeles, but it does prove that such a human-size drone is possible.
Not only is it possible, it seems significantly more likely that an unmanned drone would reach such heights than a real-life Iron Man carrying enough fuel to take off, joyride at 3,000-6,000 feet for a few minutes and then safely land. Still, the mystery hasn't officially been solved, and the appropriate authorities are still investigating the situation. In other words, stay tuned.