Just to throw in more subjective heresay, think of what might happen. I completely agree with RayChuang. The 717 makes sense for AA. They already fly 273 MD-80 type aircraft. Why not replace it with an identical plane, the 717? Okay, not identical, but yall know what I mean. And, they could use the 737 for 727 replacements only. They could launch The 717-300 as an MD-80 sized replacement. IT just makes sense. Boeing has designed into the 717 the capability to both shrink and grow. I think it makes terrific sense to AA.
And, like he said, it's not like people are lining up to buy 717s. AA could have some delivered new by the end of this year, I bet.
Just my thought.