Also, there are potentially plenty of costs that can't be recouped when a flight gets canceled. I have an 8 day vacation coming up with my lodging and rental car prepaid and non-refundable at this point. Delta has already changed my flight once in a way that would have cost me two days at my destination. I was able to reroute and actually ended up with a better schedule than my original flight but if they cancel or change it again, I might get my $800 back for the plane tickets but could lose thousands on everything else.