Common perks: * Free (capacity-based) upgrades to first class on domestic flights * Buying a full-fare economy-class (rather than discounted) ticket auto-upgr

Common perks: * Free (capacity-based) upgrades to first class on domestic flights * Buying a full-fare economy-class (rather than discounted) ticket auto-upgrades you to first class at time of purchase * Free checked bags * Free access to exit rows and other extra-legroom seats * Discount on lounge membership, and free access to lounges when you're departing internationally * Priority customer-service access * Waiving of lots of fees (for things like last-minute flight changes) Moving up through the status levels, the perks have a tendency to get pretty nice; I've done multiple flights to/from Europe where I paid for an economy-class ticket and upgraded into business class for free, for example. I've also had access, regardless of fare class, to the fancy international lounges (most recently, had a shower and a hot breakfast after an overnight flight into London a couple weeks ago).