Quick and dirty.. and I might get this a little wrong, but the gist will be there. Comair goes on strike. DAL pilots support them with lawyers guns and money. Comair says thanks. (Good enough) Then.... DAL furloughs. DALPA asks for jobs at Comair for the furloughed pilots. (I do not know the particulars) Comair MEC chairman (JC Lawson... ) decides that DAL pilots must resign their seniority numbers to come work there. DAL pilots say thank you.. well.. not really THANK you.. Hence the bad blood between DAL and Comair.

If the sequence of events is a little off it is because I have a really good, but really short memory. Anybody feel free to edit/amend/correct my post.