This thread is designed to be the definitive thread to compare airline frequent flier loyalty programs to give those milepoint.com members the information needed to make an informed decision about which program is best. For example, I currently prefer the Delta Air Lines SkyMiles frequent flier loyalty program because I reside in the Atlanta area and enjoy the possibility of unlimited free domestic upgrades whenever they are available to me. The challenge of maximizing my earning SkyMiles and Medallion Qualification Miles on connecting flights originating and terminating in Atlanta can be difficult but rewarding. Please ensure that your information is as concise and as easy to read as possible so that it will not be as difficult for fellow milepoint.com members to decide. Thank you in advance.