Hershey to BWI is a two-hour drive...WITHOUT traffic. Add beltway traffic to get around Baltimore and the trip can take an extra 30 - 60 minutes. Add to that the fact that the rental car center is not at the terminal and you have to bus it and that can add an extra 15 - 20 minutes. I guess it's a question of how much one's time is worth and how confident you are you will not get stuck in traffic. Me, I'd rather get to the airport faster and settle in with a cocktail.