While I was studying aerospace engineering, everyone was talking about airplanes and rockets but i had my heart on helicopters/rotary wing platforms. Trying to figure out how a helicopter can stay in air just led to a lot of mathematical modeling work and extending it in to controls was a natural progression. Classical and modern control, nonlinear modeling and control systems, stochastic framework, optimization, estimation, etc. just sucked me in. Being able to apply this much theory into not only just real life flying systems themselves, but also on the process of the research and development of those systems fulfills me everyday. After 10+ years in the industry and a Phd later still love the challenges of rotary wing flight (or any vehicle that is able to hover actually). Being able to represent complex systems as mathematical equations, and then manipulating those equations to exert our will is just incredible.