I use a Transpack with the zipper boot compartments. MarzNC has a nice one, but I prefer the zippers so that I can walk when it's snowing without getting the liners wet.
I packed my helmet in the checked bag last time. I figured that it was easily replaced if they lost my bag, but I would never check my boots. I think that it would be ok because my checked bag is hard sided. I wouldn't do it with a soft bag, as it might get cracked. Hidden helmet cracks would not be good.
Ruth B said "Compartmentalized" is her key to packing success. I agree 100%. But I don't like all of the zippered compartments in bags, because I can never remember which compartment I put things in. CRS. This is what I use.
https://www.ebags.com/product/ebags/packing-cubes-3pc-set/13032?productid=949922 Check around the ebags.com website for different sizes, too.
I have gloves and gaiters in a small one in my boot bag all the time. I have a little one for my boot dryer, so the cord doesn't tangle. When I pack my suitcase, I have shirts in one. Base layers in another. Socks, panties and bras in another (don't you hate it when the TSA opens your bag and your unmentionables are out in the open?). Cables and chargers for my electronics in another. When I get to the hotel, I leave my things in their packing cubes in the drawers (who knows when the drawers were cleaned the last time).
Because these are so flexible and weigh almost nothing, I have a lot of them. Different colors for different members of the family. And because they are so colorful, I never 'lose them' in the bottom of a black bag. Washable, too.
And while we are on the topic of size and weight of your carry on, if anyone gives you a hassle about the boots/helmet being too big for the overhead bin, sit down right there at the counter and put them on right in front of her. Helmet, too. If you wear them onto the plane, no one can say anything. Take them off and put them above your seat, and wear your slippers during the flight.
