Originally Posted by
cingmot
Maybe someone who does can educate us?
I'll have a go.
No airline really wants to allow standby without charge -- because flight changes are a potential profit centre (that's why airlines sell flexible tickets!).
Domestically, however, standby is a long-standing tradition. All airlines do it; American would be uncompetitive if they did not allow it.
Internationally, hardly any (do any?) offer it. Ex-LHR none of UA, VS or BA allow free same-day standby -- so why should AA?