<font face="Verdana, Arial, Helvetica, sans-serif" size="2">What's really clogging O'Hare? The small, inefficient regional jets that American and United are using. Fifty-seat jets now represent about 41 percent of the flights at O'Hare compared to just 26 percent in 2001. That means the average number of seats per departure at O'Hare dropped below 100 last year compared to an average of 110 seats per flight in 2001.</font>