Continental
Reservations: (800) 575-3335
Reservation Deadline: At least 24 hours in advance
Health requirements: Certificate within 10 days of travel
Flying restrictions: Small pets traveling as carry-on luggage must be in a soft-side carrier
Can Pet Travel as Carry-On: Yes (small pets only)
Can Pet Travel as Cargo: Yes (medium and large pets through QUICKPAK service)
Can Pet Travel as Checked-In Baggage: No

Delta
Reservations: (800) 221-1212
Reservation Deadline: Must be made in advance and based on first come, first served basis.
Health requirements: Certificate within 10 days of travel
Flying restrictions: Limited to one carry-on pet in first class, one in business and two in the main cabin per flight. No pets accepted as checked bags May 15 - September 15 or when temperatures are forecasted to be above 85° F at all points of travel. For snub-nosed breeds, the temperature must be below 70° F.
Can Pet Travel as Carry-On: Yes (small and medium pets only)
Can Pet Travel as Cargo: Yes (large pets)
Can Pet Travel as Checked-In Baggage: Yes (small and medium pets only)
Affiliates: ASA, Comair, SkyWest, and Trans State Shuttle

Northwest
Reservations: (888) 692-4738
Reservation Deadline: At least 24 hours in advance
Health requirements: Certificate within 10 days of travel
Flying restrictions: No pets may fly when the temperature is forecasted to be below 10° F or above 85° F or above 75° F for snub-nosed dogs and cats. Any pet/kennel combo exceeding 150 pounds must be shipped as freight. You can find out more by calling (800) 692-2746.
Can Pet Travel as Carry-On: Yes (small pets only)
Can Pet Travel as Cargo: No
Can Pet Travel as Checked-In Baggage: Yes

Southwest
Reservations: (800) 435-9792
Flying restrictions: Southwest does not transport pets except those trained to assist disabled persons.

TWA
Reservations: (800) 221-2000
Reservation Deadline: At least 24 hours in advance
Health requirements: Certificate within 10 days of travel
Flying restrictions: Temperature must be 85° or lower at origin, transfer & destination stations. Limit two kennels per passenger per flight. Pets weighing over 100 lbs. must be shipped as air freight. Passenger must fly on the same flight as pet.
Can Pet Travel as Carry-On: Yes
Can Pet Travel as Cargo: Yes
Can Pet Travel as Checked-In Baggage: Yes

United Airlines
Reservations: (800) 241-6522
Reservation Deadline: Must be made in advance and re-confirmed 24 to 48 hours before departure.
Health requirements: Health certificate completed by a licensed veterinarian within ten days of travel if pet is traveling with you or within 30 days if pet is traveling as cargo.
Flying restrictions: No pets are accepted as checked baggage from June 15 - Sept. 7 and any time when the temperature is forecast to exceed 85° F.
Can Pet Travel as Carry-On: Yes
Can Pet Travel as Cargo: Yes
Can Pet Travel as Checked-In Baggage: Yes

US Airways
Reservations: (800) 428-4322
Reservation Deadline: Must be made in advance and is on a first come, first served basis.
Health requirements: Certificate within 10 days of travel
Flying restrictions: Cabin space limited to one pet in first class and two pets in coach per flight. No pets may travel as checked baggage during extreme hot or cold temperatures.
Can Pet Travel as Carry-On: Yes
Can Pet Travel as Cargo: Yes
Can Pet Travel as Checked-In Baggage: Yes