The half a benydryl is the best suggestion, I have a 35 pound dog that's afraid of storms and give her a benydryl to calm her down and it works every time. Give it him/her an hour or so before you go and it will be down for the count. Some animals also like to ride, I had an orange tabby in my tractor trailer for 6 1/2 years and he never tried to leave and slept on his back driving down the road. My wife also had a gray tabby in her t/t for 5 years and both of them loved it. I've also had a 185 pound wolf that loved to ride in the bed of my pickup, so don't assume just because it's an animal they will hate it, they may love it.
benedryl (like a half a childs dose) and some catnip
Whatever occupies her the most. Does she have a special toy?
DONT GIVE IT CATNIP!!! cat can take super small doeses of melatonin give it some of that it will be fine!
put it crushed up in the cats water
Lots of cat nip