The airline Song is dead. As Seth notes on his blog, Song was a superficial attempt to create a new airline with a new value proposition. The superficial part was that it was more about the "brand is who we say we are" approach than the much more real "brand is what we do" approach.
The cool part of Seth's post is his insight that this event can be looked upon as a total failure, or as an opportunity to learn. If you can do the latter, and treat everything as an experiment to be learned from, no matter if the outcome is "good" or "bad", then you're well on your way to a process of creating ventures that starts to look a lot like design thinking.