What's the Name of That Book??? discussion

Read in the mid 90's, maybe 94-97ish. YA Fantasy about a brother and sister who are enslaved for their ability to fly. They start out in an area of that world where it's desolate/dry, and the landmass is broken up plateaus, near the equator I believe. They're used to transport goods more easily across/up+down the plateaus. The kids escape and head north(?) and eventually arrive in an area where they discover there are many people like them, and they typically serve as messengers around the world. They then join some kind of school for said messengers to become better at flying. I recall their instructor demonstrates some kind of flying whirlwind attack/defense.

English book published in the US, I borrowed the copy I read from the school library, in New Jersey. Book itself didn't seem too old, was hardcover or paperback, I believe the cover was an image of the two protagonists but I'm not sure.

TY in advance for all assistance.

I'm not sure if you're still looking for this one - I've only managed to find a Reddit post that sounds like it's looking for the same book, but is unsolved: https://www.reddit.com/r/whatsthatboo...

They remember an extra detail - 'They live on a plateau in which there is a period of time where the skies rain fire [...] they possibly believe they are related to the God of fire' - and you both use the word 'plateau', so I think that might be key to finding your book. Archive.org is currently down but I will continue searching when it's back up and running!

Maybe Child of the Air by Grace Chetwin?

Ooh, good find, Juels!

Maybe we'll get lucky. I added the suggestion on that reddit post too.

Dan, are you still looking for this book - or did you find it?