No one knows. I'm expecting the Air to be discontinued and a $999 or $1099 MacBook to take its place. This would mean a better screen, fanless design, TB3 but also losing the legacy ports.
I don't see how a new air would be any different than a MacBook Pro or MacBook 12. They've got to drop the air entirely. And there will be last year's (2017) MacBook 12 priced for $899 I bet. No changes. Or the 2017 MacBook Pro 13 no Touch Bar 128gb ssd will be $899. That should be about it. I would bet 100% that the keyboard won't change at all. I don't see any hardware changes at all to that entry level model. It'll just be a reshuffling of their product names and dropping the price.
Hopefully, unlike the current 12” MacBook, what ever Apple comes up with will have more than one port. That’s a little rediculous.
To my mind, the iPad Air had nothing to do with the MBA computer line - it was a rebadged iPad; besides, the iPad was designed to consume content, the computer (MBA and its siblings) to help you create content.
Seems to me that the iPad Mini 4 is more comparable to the MacBook Air. It hasn't been updated since 2015 and is expected to be discontinued. Have actually been thinking of getting one of these.... would be right at home with my other "Apple orphans" - two Mini's and an 11" MBA.