One thing I LOVE about UA, and helps keep me there is ability to OAL. DL has always been much harder. In days like this, I'd rather be on UA where I know if i find availability on any airline they have an agreement with, I can get them to rebook. Sad that AA planes will probably fly out with empty seats today, and DL can't get a few more passengers out because they don't have an interline agreement with AA.