How a bout an alliance with other loyalty programs. Then you could earn flight rewards by riding the bus and vice-versa: 500K DogMiles get you a free flight anywhere in the lower 48 and Canada. (what is that, like, 100 coast-to-coast RTs?) On the other hand, a flight from CVG to IAD will get net you enough miles for your return bus ride home! If you qualify for elite-level bonuses, you could even bring the in-laws back with you!