I used to just set mine in the back of the car and take it but over time, something got messed up. Now I have a tote and the machine is well-secured. No more worries.

Thanks, all. I do have to take it, so I will get a case and wedge it into the car so it won't bounce around.

Watson

You should ALWAYS anchor your machine down with a seat belt. In the event of an accident, a machine that is wedged between the back/front seats on the floor or any where else becomes a heavy projectile. You never know what another driver might do and safety for the occupants of the car is important.
I have a travel bag and a hand truck . I belt the travel bag to the hand truck to move from house/store to car. Then I unbelt the machine bag, put it in the back seat, secure it with a seat belt and then fold the hand truck up and secure it with a cord.
I couldn't afford to replace a machine that fell over and in an accident, I don't have to worry it's going to become a lethal weapon.
If you can find a rolling suitcase of the right size, it would work , just anchor it.

I usually put my machine between the passenger front seat and the passenger side back seat. I make sure the front seat is pushed back enough that the machine is not wedged but will not fall over either. Fabric/books/show and tell get tucked around it. I use one of those collapseable crates on wheels with a telescoping handle to wheel it into class. I have about used mine to pieces as I have had to zip tie the hinges. Time to look for a new one...

I do try to put the machine on the floor between the front and back seats - and wedge it so that it can't go flying or tip over.

This is how my machine travels too...I take my Janome 6600 to classes several times a year.

No you are not being ridiculous! I bought a rolling travel case for my machine which made transport much easier. I sometimes take my Janome 6600 to retreats or classes. It is a heavy machine and carrying it from the house to car or car to wherever your class is, may be your biggest challenge. I highly recommend getting a rolling machine case. There are plenty of them out there that are not as expensive as the Tutto bags. They will protect your machine and enable you to get it from one place to another without injuring yourself or your machine. As a bonus, you can add fabric around the machine as extra protection for the machine and extra storage/transport space.
Do a google search for sewing machine rolling cart and you can get an idea of the range of carts available. Just be sure to measure your machine to get the right size.
As a side note: I took my 6600 to a retreat years ago, set it up on a small folding table and the table collapsed,my machine fell to the floor! I was horrified that I had killed my machine. Picked it up, set it up, and it was OK. Used it during the retreat with no issues but took to my repairman as soon as I got home, just as a precaution. He checked it out and told me "these machines are tougher than they look". Not a thing was wrong with it. Now while I don't advise letting your machine fall or get mistreated in any way, it is comforting to know that they are tougher than they seem.

I bought an inexpensive ($60) lightweight Kenmore at an estate sale just for classes. I know that I'll just be cutting and piecing at a class, so I don't need anything to accommodate a full-size quilt. At Goodwill I bought a luggage cart ($3) and onto that I zip-tied a plastic crate ($5). The machine fits both into the well between the front and back passenger seat and also fits into the crate along with fabrics and tools for transport. Make sure to bring an extension cord - more than once the shop hasn't had enough for everyone. Have fun!!

I have a rather inexpensive Brother that is my tag-a-long machine. I don't worry about it being damaged. I take mine almost weekly to a sit-n-sew at our LQS. The LQS has a small classroom, but it is laid out well, and the cords are out of the way. When I go to my guild sit and sew or retreat, again, we are mindful of the cords and safety. Many of my friends have expensive machines, and they do have the well made totes for them. I actually have one of the "Land's End" type tote that I got at AC Moore that my Brother travels in.