We recently came across an article from the folks at the Pocono Record that details some of the basics:
While no one can guarantee a trouble-free trip, the good news is that the vast majority of pets traveling by air get where they're going in fine shape. Even better news: Careful planning on your pet's behalf will help make things go even more smoothly.
Animals move through the airline system as unaccompanied cargo or as travelers' baggage. Unaccompanied pets and most animals traveling as baggage travel in pressurized cargo holds, while some small pets are allowed into the cabin as a carry-on. Before your pet flies:
Talk to the airline. Some carriers ח especially the no-frills companies don't take animals at all. Those that do have limits on the number of animals on a flight, typically two small pets in the passenger cabin, and not much more than that in the cargo hold. You also need to know where and when your pet has to be presented, and what papers ח health certificate, and so on you'll need to bring. Airlines charge extra fees even for those pets who fly in a carry-on bag, so ask about it in advance so you won't be surprised. Also be aware that some airlines won't ship pets in the summer months, with embargoes starting as early as mid-May.
Be sure your pet is in good health. Air travel isn't recommended for elderly or ill animals, and is likewise ill-advised for the pug-nosed breeds of dogs and cats. These animals find breathing a little difficult under the best of circumstances, and the stress of airline travel may be more than they can handle.
For pets who'll be traveling in the cargo hold, use a hard-sided carrier designed for air travel, and make sure it's in good condition no cracks in the plastic, no rust on the grating. The crate should be just big enough for your pet to stand up and turn around in. Check and double-check that all the bolts securing the halves of the carrier are in place and tightened. Pets that are small enough to ride in the passenger cabin will be more comfortable in a soft-sided carrier.
Carry-on pets should have a collar and ID tag, but that's not safe for pets traveling below. Instead, put an ID tag on a piece of elastic around the pet's neck, and make sure contact information is written large and indelibly on the outside of the crate. A water dish should be attached to the inside of the door grate so airline personnel can add water without opening the door.
Consider travel conditions. Don't ship your pet when the weather is extreme or when air traffic is heaviest. Avoid peak travel days, and be sure to choose flights that are on the ground when the temperature is neither too hot nor too cold, not only at the departure airport but also at the connecting and arriving airports. In summer, a night flight is likely better, while the reverse is true in the winter.
Choose a direct flight. If that's not possible, try for a route with a single connection and a short layover. Better yet: Choose a direct flight with an airline that has special handling available for pets, keeping them off the tarmac until just before flight time and transporting them to and from the plane in a climate-controlled van.
Ask about your pet, persistently but politely. Make your presence known! Confirm that your pet has been loaded and has made any connection en route. It would not hurt to do what you can to make your pet stand out as more than mere cargo. One person I know puts a prominent sign on her retriever's kennel when he flies. "I am the beloved pet of a 5-year-old boy," it says.
Contrary to popular belief, it's generally safer for your pet not to be tranquilized before flying. The combination of high altitude and limited oxygen is a challenge your pet's body is better prepared to meet if he's not sedated.
It seems that the truth is starting to rise above the myths, that pet relocation by air - when done right - is the best option for any live animal!