that i could do aerobatics with. it's been a great airplane. >> july 22nd, 2007. bill leff and his son greg are flying to the air venture event in oshkosh, wisconsin. >> it's a collection of pilots that really enjoy airplanes of all kinds from little home-built airplanes that they build out of steel tubing and wood to big jets. oshkosh airport becomes the busiest airport in the world for that week. there will be as many as 13,000 airplanes. >> during the venture, the population of oshkosh skyrockets as people pour into the city on highway 41. >> it's busy all day because people are going to and from the air show at all different times. >> the leffs are having an uneventful flight as we cross the wisconsin border. >> the engine had been running smoothly. i even commented to my son on how good things were. >> but things change quickly. 20 mimes south of oshkosh, over fond du lac, the engine dies.