How Do I Wirelessly Sync Movies In iTunes On My Mac With My iPad Pro?

I got the new iPad Pro for Christmas. I want to put some specific movies on it for an international flight. The movies are in iTunes on my Mac, but not purchased from the iTunes store. My Mac doesn’t have a USB-C port, but I thought I remembered that it could by synced over wifi, but I can’t figure out how to do it. When I go to File > Devices in iTunes on my Mac, “Sync” and all the other menu options are grayed out. Is there a way to accomplish this, or will I need to purchase an adapter for a wired connection?
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Cameron