When you have a pet and you have to travel, you're stuck with the complicated choice to either board your pet at a pet hotel, leave them with a pet sitter, or take them with you (if that's even an option). While boarding your pet somewhere can be expensive and stressful, how much it costs to travel with a pet on a plane can often be far more expensive. That said, it's up to the airline to name the price for your pet's travel, and some airlines are far more reasonable than others.
With some airlines, you'll find that your pet's ticket is more expensive than your own. Considering the fact that if you have a small pet that fits in a floor-stowed carrier, you're giving up your personal space and carryons to accommodate them, it's outrageous to pay such a high price for your pet to travel with you. What's more, most airlines have a maximum number of pets that they permit to be on board for each flight, so if you book your ticket late, there might not be any more room for pets allowed. Yes, really, some airlines actually won't even let you take your pet with you on your flight, even if you are willing to pay that high price.
If your dog is flying in cargo, aka your dog is too large to fit in a carrier in the cabin, the price is a bit more reasonable, but the health risks for your pup are higher. In fact, during the warmest months of the year, this service is suspended for safety reasons. Here I've broken down the price to travel with your pet by airline. Remember, in order to bring your pet on the plane, you also have to have a pet health certificate which is a document that your vet must issue within two weeks of your departure. The cost of this certificate can be close to the price of a regular vet visit, which easily brings the cost of flying with your pet into the flying with a human range, so make sure you have extra money saved for that, too.