I see this as well. Students particularly. The Air got popular when the price dropped. Initially, everyone also criticized it for being too expensive and underpowered. Look at this thread and tell me it doesn't sound like they're talking about the new Macbook: http://forums.macrumors.com/threads/why-is-the-macbook-air-s...

My speculation: No upgrade for the Air but I think they'll announce a new lower price for the new Macbook as well as somewhat upgraded internals. They may lower the Air price a bit and keep it around or perhaps kill it outright. Everything about the Macbook seems like it's made to replace the Air apart from the price.