How do you guys carry bicycles inside?

Just an idea but I built a bike rack that uses the crank arm to hold the bikes upright. It has a square tube with a slot cut for the peddle. This is what all the shuttle vans typically use. I made mine to hold 3 bikes and it works really well. I just set it on the floor in the trailer on a mat or piece of carpet and with the three bikes it does not move at all.

Here is a pic of one https://forums.mtbr.com/cars-bike-racks/shuttle-van-type-rack-holds-crank-arm-890794.html

Typically the shuttle companies drop a rag over the top of the tube and push the crank arm down through the rag to protect the crank arm.