Well, I have had the opposite occur than most of the posters on this thread.
I have a softside travel crate that holds upto about 34lbs. Bailey used it when he was smaller than his now 76lbs and Chloe used it until last week she is now 38lbs and 5 months old.

When Bailey was little he puked in the crate all the time until I let him ride out in the backseat........no puking, he loves to look out the window. Chloe only puked a little bit, sometimes. She now rides in the back cargo area (I have a stationwagon type car) on a non-skid fuzzy cargo coverup. No puking although she likes to ride only looking out of the back window. So, for these two, being confined to a crate wasn't what was good for them. They both ride beautifully. The vet said it was probably the motion, coupled with the fact that they couldn't see outside, said kind of like if someone put me in an small confined space and I couldn't see out and began to move it rapidly and he said that some folks as well as animals get disoriented and some do not.