Most people who work for ThoughtWorks in the US travel for a living, so we spend a fair amount of time talking about travel. Lately, we have noticed a pattern on cancellations and formed a theory: Flights towards an airline hub are less likely to be canceled.
Most of our team currently flies United between Chicago and Newark. One member flies the same route on Continental. Chicago is a United hub, while Newark is a Continental hub. When there is bad weather on Thursdays, Continental will often cancel all of its flights to Chicago. United, however, generally makes it out. Likewise, on Sundays, United is more likely to cancel all of its flights to Newark, while Continental does not.
Our reasoning is that airlines are afraid that their planes will be stranded in non-hub cities. Continental does not want to send its planes to Chicago if it fears that they will not make it back (many of the flights bounce back and forth between these two cities). If the planes are already out, the hubs want them back, so flights towards the hub will probably make it out.
Taking this theory into account, it is better to fly an airline that has a hub in your home city. Flights out are more likely to be canceled, but at least you spend the night at home. Returning flights are less likely to be canceled, so you have a better chance of getting home.