For you best start would be elliptical. It can give you great workout in 20-40 minutes. Since you travel often you should have access to it at hotels you stay.
Others can correct me if I'm wrong, but since you "fat", I don't think you should try to start running at the moment. Although that is great way to lose some weight, you don't want that extra fat to stress your knees, until you lose few.
1999 E36 ///
M3 Convertible MT Silver / Silver (99.99% stock)
2006 E90 325i