It's a big zombie, one the Japanese government (so far) seems unwilling to let disappear, and Delta's Tokyo hub operations and trans-Pacific flights also stand to benefit from the reduction in competition. I think it's a pretty wise investment for Delta, actually -- and I'm a little surprised since Delta seemed to take Asia for granted.

Besides, AA (and its partner TPG) are more than willing to play the same game, so they also see something of value in providing cash to JAL. They don't have a great hand to play, though. JAL is a de facto ward of the state, and if the Japanese government is pushing hard for SkyTeam membership (i.e. a cartel enhancement strategy to save some piece of JAL), AA has a tough challenge to overcome that.