When it comes to how long a cat can travel without peeing, there is no definitive answer. Every cat is different and will have different needs when it comes to using the bathroom. Some cats may be able to hold their urine for long periods of time while others may need to stop more frequently. It all depends on the individual cat and its bladder capacity.
That being said, if you are planning on travelling with your cat, it is always best to err on the side of caution and make sure that there are plenty of stops along the way so that your cat can relieve itself as needed. A long car ride or plane trip can be stressful for a cat, so making sure that they can use the bathroom as needed will help reduce their stress levels and make for a more pleasant journey for everyone involved.