Is there a way for me to assure that 2 or 3 particular articles or books are on my iPad?

I have a 1MB iPad Pro. I have lots of books and articles downloaded to the Books app. I do not need many of these items to literally be on my iPad. I am fine with them being in the cloud, where I also have lots of space.

HOWEVER, often when I fly, I have a recent work assignment (like reading tax regulations or other publications) that I want to know for sure will be available while I am in the air. I don’t need these items permanently on my iPad. I just need them on there TODAY, because while I am flying, I won’t be able to access the cloud. After I land, I don’t care if they go back to the cloud. Next week, it will be something else that I want on my iPad when I fly THAT time. I don’t need for EVERYTHING to be on my iPad, and it’s not the same thing each time.

Is there a way for me to ASSURE that 2 or 3 PARTICULAR articles or books are LITERALLY on my iPad (not in the cloud)THIS TRIP, and ASSURE that 2 or 3 DIFFERENT articles or books are LITERALLY on my iPad (not in the cloud) NEXT TRIP?

PLEASE DO NOT send some generic advice about how to free up space on my iPad. I have asked a very specific question, and that is what I need an answer to. Thanks!

[Re-Titled by Moderator]