Investors like AeroVironment's drones, but its expensive stock price? Not so much. AeroVironment (AVAV -7.66%) stock is wrapping up a volatile week, but ending on a weak note. Heading into the holiday Tuesday, the company known for its battery-powered small military drones announced another foray into hydrocarbons -- a 215-pound drone that runs on petrol. Investors liked the idea of the company broadening its product array, and the stock hit a new all-time high closing price of $219. This momentum continued ...