The pilot of the biplane that pancaked into the runway at Wheeler Downtown Airport before a stunned air show crowd Saturday described himself as obsessed with flying. Bryan Jensen grew up on a farm in Iowa, took his first flying lesson when he was 13, soloed on his 16th birthday and as an adult flew jumbo jets for Delta Air Lines, according to a website promoting his passion for aerobatic flying. He’d been a stunt pilot the past 15 years, when not in the captain’s seat of a 747.