Table 1: System* Quarterly Operating profit/loss margin (in percent),,,,,,, Passenger Airlines by Group ,,,,,,, Ranked by 4th Quarter 2006 Margin ,,,,,,, (Operating Profit/Loss as Percent of Total Operating Revenue),,,,,,, 4Q 2006 Rank,,4th Quarter 2005 (%),1st Quarter 2006 (%),2nd Quarter 2006 (%),3rd Quarter 2006 (%),4th Quarter 2006 (%),4th Quarter Operating Profit/Loss $(Millions) 1,Regional Carriers,8.9,9.3,8.1,8.9,10.0,245 2,Low-Cost Carriers,1.8,2.5,10.8,3.3,2.7,131 3,Network Carriers,-7.3,-3.3,7.5,5.4,1.7,393 ,21-Carrier Total,-4.5,-1.3,8.1,5.4,2.6,769 "Source: Bureau of Transportation Statistics; Form 41, Schedule P1.2 ",,,,,,, * System = domestic + international ,,,,,,, ,,,,,,,