11.   And private carriers will have to sign up.

12.   As a condition of approval, the two carriers have to give up Heathrow landing rights to four rivals including Delta.

13.   Because the equation is a function of airplane size and distance traveled, major carriers have even lower costs per seat mile.

14.   Because the unspoken secret is that the established communications carriers that still have unions basically wish that they did not.

15.   Between those savings and their own rate increases, he says, the long-distance carriers have no justification for passing along the new fee.

16.   Bigger carriers have to worry more about reliability and by necessity are more conservative in their network design.

17.   All wireless carriers have capacity problems.

18.   But even as the domestic economy remains strong, carriers are having difficulty maintaining past earnings levels.

19.   But no major carrier has a tighter stranglehold on its hub airports than Northwest.

20.   But not all carriers have equally deep pockets and resources.