Complex sentence: Captain Thompson has also enjoyed a twenty-five year tenure with Delta Air Lines and has served as Commissioner, Massachusetts Aeronautics Commission as the longest serving Commissioner in its history, having worked under both Democratic and Republican governors.
Split into simpler sentences: Captain Thompson has also enjoyed a twenty-five year tenure with Delta Air Lines and has served as Commissioner of the Massachusetts Aeronautics Commission. The longest serving Commissioner in its history, he has worked under both Democratic and Republican governors.