Originally Posted by
kkjay77
CO, DL, NW and US all offers space available free upgrade for elite members while AA also upgrades its top tier EXP members for free.
Clarification: AA PLT and GLD also can upgrade using 500 mile stickers - which you earn by flying, so this to qualifies as "free." If you don't have enough stickers, then you can purchase the stickers for a nominal fee. All AA upgrades - regardless of status - are space available.