DL/NW did not fence ANY domiciles. They fenced DL pilots off the 747 and NW pilots off the 777 for, I believe, 5 years. Otherwise, no fences of any kind. They were quick to move equipment around, too ... 777 and 737 to DTW, 320 to ATL, NYC, SLC, MD88 to MSP, and so forth. The 747/777 fences are going to expire relatively soon.

UA/CO did not fence ANY domiciles, either. They fenced CO pilots off the 747 and UA pilots off the 787 for 5 years. Otherwise, no fences of any kind. Before they even had one list, they had opened CO 737 domiciles in ORD and DEN, and UA 767 and 320 bases in IAH.

A review of the last several seniority arbitrations reveals a solid trend. Arbitrators prefer to avoid lengthy or complicated fences (the Roberts Award from the Northwest/Republic merger is a case study in how difficult and contentious heavy-duty fences are) and "let the list do the work". Fences of limited duration and scope, usually restricted to higher-paying (i.e. widebody) equipment, and almost never do they look at domiciles. (AA/TW was the last integration I can recall that attempted to fence any domiciles, and that wasn't arbitrated.)

Were I a betting man, I would speculate a fence of (at most) 5-7 years around US 330s and AA 777s, leaving the rest to open bidding. I would be highly surprised if any domicile fences were in the offing anywhere. Here is why ...

Look at AA and US. AA is roughly double US in size, but both have enormous fleets of Group 2 aircraft. For example, AA has a massive MD-80 base at DFW, and US has a massive A320 base in CLT. The two pay exactly the same thing, so all else being equal, the only reason one would bid between them would be to improve quality of life. Given the enormous number of commuters we all have from each other's domiciles, preserving those quality of life improvement opportunities for both sides is worth what will likely be only a very small tradeoff in relative seniority bidding power between the positions, depending upon the final composition of the list.

Just my $0.02 ...