This one (report) is always a little suspect (although the carriers don't mind quoting it if they do well). Firstly, in spite of a management that seems to have a disconnect with the traveling public, US inflight performance is quite decent. The fact that the low cost guys do so well (and thus push others down the list) is probably more a case of meeting lower expectations. That is to say, the customer knows what they are getting. In the case of the big boys, it seems like they are suffering from an identity crisis.