Originally Posted by pdx1M

UA made a strategic choice to make their east coast hub IAD - don't know that is better or worse than splitting ops with NYC. It did seem to work for them though and general operations in the DC airspace are better than the NYC airspace. In any case I don't think "small" necessarily maps to numbers of ops but rather to system complexity. CO had essentially 2 hubs (and a few lesser hub-ettes) so support. If you look at a connectivity graph with 2 hubs it is pretty simple - a trunk between the hubs and the spokes. The new airline has SFO, DEN, IAH, ORD, IAD, EWR as major hubs and it has more hub-ettes with LAX, GUM, NRT, CLE, etc. The connectivity graph for a 6 hub map is much, much, more complex mathematically. The assignments of aircraft to such a graph, the routing of passengers and crews through it, and most of all the re-route/recovery options (and requirements) are all vastly more complex in such a graph. It seems to me that it is this complexity that is killing them at the moment. UA operations understood this level of complexity because even a 4 hub graph is much, much more than twice as complex as a 2 hub one. This isn't bashing what CO was - it is just the mathematical reality of the complexity of graphs - and scheduling an airline is an exercise in mathematical optimization.