Is there a way to schedule airplane mode for iphone?
Using a Shortcut for that would probably be the best solution. If you have any experience with programming you could probably whip something up without too much effort, or I'd recommend checking out the shortcuts subreddit. 

There's also a chance somebody has already created what you're looking for, I didn't find anything in a quick glance through this gallery, but you could possibly find something with some digging. 

I hope this helps move you in the right direction!