I travel to shows all over the east coast, and I use the hard cat carrier. I feel it is more secure, should they get upset, or something should happen.

I also use the bigger ones, so they can stand up, move around, or comfortably lay down. Its kinda like, if you had to travel, would you rather be in a large comfortable vehicle, or squished in a small vehicle.

If you want to get your cat, so she walks right in the carrier, when you open the door, feed her in the carrier, wait a few min after she has finished, then let her out. She will associate the carrier with good things, the food, and she will learn nothing bad happens to her, and she eventually gets to come out.

I also put in 2 towels, so it is soft for them, and a few toys, so they have something familiar from home. Mine walk right in, when I get ready to load them, for a show or the vet. :-)