But the true "canary in the mine" is in fact cabin crew resignations. As was stated above, early resignations are happening at a record pace never seen before.
Whatever the reasons, it is happening. 2015 will see a greater number of pilot resignations than years past. Pilots uprooted from their homes of 20 years may have the option (and money) to retire instead of putting up with continual erosion of the T&Cs that don't seem to stop, continued hiring by legacy carriers not just in the US, and the general feeling of frustration with rosters, etc.
Heard of one pilot very close to 777 upgrade that resigned to go fly right sear of an RJ in the US. He figured he would have an easier time getting hired by a legacy after a six month upgrade at the regional than stay here as a 777 captain. Smart move? Who knows at this point. But that tells of the overall dissatisfaction of daily work here.
Ask anyone from fleet what JA deals with daily? It's not operational.