Sixt has an established program that gives instant matches to Sixt Platinum for high Elite members of United, Delta, US Airways, American, Hilton and Marriott programs. The Sixt Platinum status gives a one car class upgrade, a 15% discount and, in most merkets liability and collision insurance also. Those of us who've been using Sixt for some time mostly like their fairly inexpensive MB and BMW cars also. For details the easy way is to Google sixt+ your chosen partner, which gives you the Sixt partner page. I chose Delta as mine and was processed for the Platinum upgrade in less than a day. Sixt then rewrote all my reservations to get the lower rates and even included one which was prepaid. I rent from Sixt exclusively when I am in a location they serve. Their North American coverage is limited but is growing rapidly from a beginning in 2011.