otralot - CO definitely has different policies as other airlines. Like the AA examples I wrote earlier. I am not saying who's right and who's wrong, just different. Like others have said, CO certainly know for sure when many of their flights are taking off in Europe that EWR will have problem. I haven't checked DL, but AA don't divert their flights. They don't fly them.

But it's also due to fleet and route structure. AA has Chicago and DL has Atlanta that can accept a lot of passengers. So, they can afford to cancel the flights - especially on a winter weekend day. But CO has nowhere else to put their customers.