Complex sentence: Even before the advent of airplanes, Post participated in balloon races including the Gordon Bennett races of 1906,1908,1909,1910 and 1911.
Split into simpler sentences: Even before the advent of airplanes, Post's interest in transportation extended from the ground to the air. He participated in balloon races including the Gordon Bennett races of 1906,1908,1909,1910 and 1911.