The Barstool Pirates take flight during the Red Bull Flugtag event at the Charles River on Saturday, Aug. 20. The unique event featured teams from all over Boston who spent several months designing and building flying machines that were launched into the Charles on Saturday with one rider. Some, like the Pirates here, followed their contraption on foot. The event attracted thousands of people to the Esplanade where spectators marveled at the attempts to fly. Flugtag, which means “flying day” in German, pushed the envelope of human-powered flight, but competitors needed more than airtime to reach the podium. Teams were judged on three criteria: flight distance, creativity of the craft, and showmanship. The teams competing on Saturday were chosen from an applicant pool that numbered more than 200 submissions.