I swear by SM water bottles. They’re durable, don’t leak, and they’re easy to wash and sanitize (which is super important during cold and flu season). I like this size for my preschooler and he used it in daycare as well.
Simple Modern 14oz Disney Summit Kids Water Bottle
Hear me out: start the elderberry and vitamin C before flu season. You’ll thank yourself. The last 2 years I started the kids on elderberry in August and managed to skate through all the beginning of the year bugs with none.