A

• Alaska Air http://www.alaska-air.com
• American Airlines http://www.aa.com

C

• Continental http://flycontinental.com

D

• Delta http://www.delta-air.com/index.html

N

• Northwest http://www.nwa.com

S

• Southwest http://www.iflyswa.com

T

• TWA http://www.twa.com
• Tower Air http://www.towerair.com

U

• United Airlines http://www.ual.com
• USAir http://www.usair.com