Some more nervous pets may need a certain amount of training before travelling. Positive reinforcement can be used to make the animal associate travel with pleasure.
For instance, a client with a dog that is nervous of car travel may help ease the problem with a series of training sessions. First they entice the dog into a stationary car (with the engine turned off), and offer a reward. Then, once the dog is happy with this, they repeat the procedure with the engine running. Finally, very short journeys can be introduced. These trips are increased in length gradually, until the dog is able to travel relatively long distances.
Good behaviour should always be rewarded (with food and reassurance), whilst undesirable behaviour such as barking and whining should be ignored. Clicker training can also be used in conjunction.
Pets with a severe phobia should be referred to a behaviourist.