I bought the first generation macbook air (with SSD) when it first hit the stores and it was almost worth it just for the "wow" factor at conferences. I put it on the table at a meeting and an EA exec yelled "hey, why don't you just slam your huge elephant dick on the table?". That was worth $10 right there.
Anyhow I always found it to be unbearably slow - particularly when browsing to a new web server in a session. As if the dns lookup was.... thrashing somehow. I figured I was too dimwitted to figure out the problem after doing a bit of research, so it's rotting on the shelf.
Also, Marco is right - it's way too big to use in coach when the person in front leans back. Thankfully.... Ipad for air travel. Be curious to see what the 11" is like.