DL has been innovating a bit more than CO -- new interiors, new IFE, more new routes.

International flights seem to be the bigger money makers these days. And while CO has been adding new routes, DL has been adding them faster, and each time DL adds a route, they serve it with a 763, not a 757 like CO.

We have to give credit to CO management for thinking up this strategy (DL is just copying CO), but DL has more planes and is able to execute faster than CO.

Plus with the DL reimaging (new interiors, uniforms, IFE, etc.), DL is attempting to have a "coolness factor" that none of the other majors are trying to emulate.

So when you take all this in consideration, I see how DL's valuation may be higher than CO's, as there really is potential for DL to succeed if their risks pay off.