Being enclosed in limited space for a long time can be physically and mentally disturbing, this applies for us humans as well as for your pet. So how long will it remain comfortable inside a pet carrier? It depends on the type of carrier you have chosen for your pet.
Pets tend to feel scared inside an enclosed space, even though most carriers have everything that will help them stay inside comfortably. Most of the carriers are provided with soft lining, airy wire meshing, easily opening shutters, etc. However, after some time your pet is bound to feel tired and longing to exercise those cramped muscles.
When traveling in your car, try and give your dog a small walk every 2-3 hours, this will simply help you dog to relieve it self. Instead of giving your dog food in moving car, you can give your dog some food during these breaks. It simply helps the dog to eat at ease. A 10 - 15 minute break is enough for your dog or pet to relax and return back to the carrier.
Pet carriers are of different types; some of these are made of solid plastic and contain enough aeration so your pet does not feel claustrophobic. There are also some very stylish ones which would be useful for you if your pet dog is small. These can be carried like a shoulder bag and also allow the pet to keep its head out of the bag.