If you have a computer, then this is one of the best operational games out there, super deep, super detailed, NOT recommended for the non-detailed oriented.  Fetures include: a 1-2 or 3 days “turn”, leaders managment, pilot training, resources managment, oil, fuel, supplies, production, super accurate OOB, a 40 km map that covers from the western US to India and Mongolia to New Zealand.  Best played PBEM, but playing the AI is good too.  Very well supported by a very dedicated group of designers/players.