Snowmobile Trailers

I have a snowmobile trailer and have been a little trouble keeping the air in the wheels. I know the solutions but it crossed my mind that if someone makes a semi-soft wheel with no air in what would solve the problem. Does it exist?

Yes they do. The simplest solution is just to your current tires filled with urethane foam. It is not usually done on the tires at high speed because of the difficulties of balancing, but this can be done.

There are a number of other techniques used on armored vehicles to prevent flats if the tires get shot up.

I do not know where you live, but here in Australia it would be dangerous to use on wheels you see any type of trailer
I suggest you go to a service tires and wheels were repaired this

do not want him to be the man shake your trailer would break things so hard two reasons goes flat tire or a hole or not a good seal
a tube would take over the air .. and correct the problem