There are lots of little differences, that may add up to being significant to you or not. A couple threads went through thus a bit earlier in the year regarding 2014 models. Here are a couple cut a pastes from them....
(2) The interiors of the Whitehawk and the Jayflight look largely the same. However, I notice the Jayflight has:
Porcelain toilet with foot flush
Much greater cargo carrying capacity
Much greater water capacity
30 lb gas bottles versus 20 lb gas bottles
MSRP slightly below Whitehawk (about $1K)
And here were my observations back then about all different lines Jayco offers ...
Whitehawk -- Doesn't offer larger 8cf fridge, toilet is plastic not ceramic, bed and overhead storage doesn't have hydraulic rams to assist, smaller tank capacity, smaller LP tanks, etc
Swift vs. JayFlight -- Swift seems to have lower holding tank sizes, lower GVWR, missing hydraulic rams in swift like Whitehawk, certain swift floor plans have side mounted AC, non-ducted AC, no thermostat for AC, Smaller LP Tanks, no LP tank covers, no sink covers
JayFlight -- More standard options over Swift but still very similar. I find a little nicer interior finish, now available in fiberglass -- but not gelcoat fiberglass, tank covers, sink covers, rams, etc.
Eagle -- Most amenities available. Gel Coat Fiberglass, nicest interior finishes, domed ceiling, hidden propane, etc
2007 Chevy Duramax LMM/Allison
2012 Jay Flight 29QBH
2012 Jay Flight 26BH (Sold)