Scott Kirby was until today President (#2 to the CEO) at American. He's now President (#2) at United. It's not often you see such a high ranking executive move from one company straight to another. American has appointed its COO Robert Isom as President.
http://newsroom.united.com/2016-08-29-Scott-Kirby-Named-President-of-United-Airlines
http://hub.aa.com/en/nr/american-airlines-group-names-robert-isom-as-president-8-29-2016