Airlines sell travel kennels of molded fiberglass, also lightweight and versatile. If you expect to travel by air with your dog, you would do well to purchase an airline style crate at the start and use it at home too. Size 400 is usually adequate for an adult Siberian. Training a puppy or dog to accept and enjoy his crate is much like leash training. It requires only common sense, patience and consistency.
Some dogs accept crates readily, especially if they are given something to chew on.
Even those who object at first will soon catch on, curl up, and go to sleep - even on an airplane. Just remember, don't reward a dog's objections by talking to him or opening the door to the crate - instead, just walk away, letting him know that this is nothing to be upset about. Return after a short time at first, praise him, and let him out. Use common sense, and only crate him when he is not in need of relieving himself, and preferably when he is ready for rest or sleep anyway. Increase the time spent int the crate gradually, up to a few hours.