I will be moving for a year about a 10.5 - 12 hour drive from home (depending on the number of pee/driving breaks) with both of our Bengals.
I drive a VW Golf TDI and while it can haul the majority of what I need to take (bare essentials--clothes, a few sheets and towels, a few pots/pans, etc, but no furniture), I'm struggling to find room for both of our rigid carriers.
One is fine, but the other is too small and won't fit anywhere reasonably with the other one, so I'm looking into soft-side carriers.

Amazon is full of horror stories about breaking shoulder straps (wouldn't be an issue, I'll hand carry them in and out of the vehicle one at a time), escaped pets, broken zippers, and much smaller than advertised. My boys are fairly large at 17 and 14 lbs and would NOT be able to spend one hour, much less 10 - 12, sharing space in a carrier, so I'm going to need two reasonably priced carriers. I have tie-down brackets in multiple places in the car, once the seats are laid down, so them sliding is not an issue (I've done it with the hard-side ones already). I'm wondering what others use in regards to soft-sided carriers that are roomy enough for longer travel for bigger cats. They're only going to make the trip once out and once back, then just trips to the vet, so I'm not worried about long-term or frequent use issues. I'd prefer top-loaders as Maxwell is a master escape artist when he puts himself in reverse... like a dang armadillo, balling up and rolling backwards.

I'm well versed in travelling with a cat, though my moggie was much more low-maintenance. But, I already have plans for stops, room for a litter box and food/water access during breaks, towels with our scent on them. And, I started working on car training this week. Both wear their walking jackets during travel even to the vet and they seem to work like Thundershirts... calming both and keeping them from jumping/climbing about when stressed. I'm leaving in about 6 weeks, so any thoughts would be really helpful in regards to the carriers!

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I would suggest hard-sided carriers. You've said you can tie the carriers down, but I'd be worried about slamming on the brakes to avoid a stupid driver and have everything else you're hauling come crashing down onto the carriers. I don't know how much protection soft-sided carriers would give the kitties. I have a hard-sided carrier with a top door which makes it so simple to put the cat in. Holds a cat up to 20 pounds (my cat is 13 pounds), but the handle on the top feels as if it could break off, so I tend to hold on to the bottom of the carrier too. I've moved before with a kitty and her carrier was on the front passenger seat where she could see me and I could see her. Will be moving again in a couple of years with a 13-1/2 hour drive and would probably do the same with my Bengal. With two cats, it could be different. It's great you're getting them accustomed to traveling in a car. Mine howls the entire time. As long as there is ample room in the carrier for the cat to turn around, you should be fine. You might head to a local pet store and check out what they have. Good luck with the move.

The soft sided carriers would actually fit more securely given the kinds of things that I will be transporting and how I am also securing the rest of the items. One large rubbermaid tub (blocking off the other items), secured into place (via sidewalls and floor) to provide a kind of sheltered area for the cats, the litter, and the provisions they will need access to just behind the drivers and passenger seats. Unfortunately, the hard-sided ones just won't fit.
The soft-sided carriers can fit where there hard sided won't because of the extra space where the lip on the sides and extra pieces jut out.
They can't be safely secured next to each other without losing almost 12 precious inches of space horizontally.
The tie downs I'll be using are actually on the side walls inside the hatch and rear passenger area, which will keep them from sliding front to back and also side to side. The front seat is not an option as I have front, upper-side and side airbags (two-door car, so the side ones are huge) and in the event of an accident, no carrier would be safe.
I'm kinda stuck between a rock and a hard place, because there are things that I need to have and things that they need and very, very little space.
I'm thankful for the input to have to think of things from every angle, though. I'm glad I have time to process and problem-solve!

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