Back in the days that I worked for TWA we flew dogs all the time... they get pretty good care as most people like dogs and watch out for them.... just make sure the kennel is big enough for them to stand up comfortably, to turn around and have plenty of space for them.... talk to your vet about traveling with them... he may recommend a tranquilizer for them or not, depending on the vet, the dog's temperament and such... you will need to make sure you have a health certificate for each dog to present to the airlines... they will either attached the cert to the kennel or the airwaybill.... depending on policy... the cost isn't cheap... don't know now what it costs as I've been gone from the airlines for over 30 years, but in my day, the rates were 150% of normal cargo rates... plus they charge on volume of the kennel, not the weight.... airline charges are weight or volume which ever is greater... volume is calculated by multiplying the length x width x height in inches of the kennel and dividing by a weight factor... it's been a while since I did any calculations, but I think most carriers use 144 as the weight factor... TWA sold the kennels as they couldn't be re-used so that was also another cost....
Not to scare you, but you want to be very sure of the size of the kennel... I have seen some disasters because the dogs didn't like being caged or the kennel was too small. If the origin and destination airports have animal shelters, it's good to work with them so the can ship and receive the animals... less stress on them.