For long trips, it's important to choose a carrier that will be comfortable and safe for your dog. Check out Dog carriers & bags https://pawious.com/collections/pet-carriers-bags-travel. Such bags have many useful features: good ventilation, soft bottom and easy access. If your dog is worried about closed spaces, look for models with ventilation holes - this will help her feel calmer. It is also important to consider the size of the pet. He should easily stand up, turn around and lie down. For a car trip, it is better to choose a model with a hard bottom and reliable locks. I recommend checking out this site about dog carriers, they have different options for long trips, and you can find one that fits all your needs.