Complex sentence: If the plane would have successfully completed its journey, Lindbergh would probably not have made his own historic flight, and might instead have set his sights on crossing the Pacific, which might have prevented Amelia Earhart from attempting her own journey.
Split into simpler sentences: If the plane would have successfully completed its journey, Lindbergh would probably not have made his own historic flight, and might instead have turned his eyes towards the Pacific. Which might have prevented Amelia Earhart from attempting her own journey.