Well i ended up going with the duffle bag, and bought a North Face Flyweight pack for day trips. It folds into itself so that way it won't take up too much space in the duffle during flight. It's funny that you all suggest i go to REI, i work as a supervisor at an Any Mountain, one of REI's competitors. I was about to get my pack for 40% off cost. that's a $50 dollar pack for $15.