As others have said above, the Air should (far as I know) come with at least two of the stems with plastic tips. They're really short and the airflow is pretty decent, although I don't have anything to compare it against, save the stems I got with my Air.
Dunno if it's just me, but the two higher heat settings seem to drain the battery a bit quicker. The unit definitely has trouble maintaining the temperature at the two highest settings. Green and below is when it seems to shine for me (200 Celsius and down).
I think any issues I've had with airflow have had to do with me packing it too tight / tamping it down too much. I've used the tiny Air stems for the most part, only realizing that I had the rubberized vape sleeve and the super long (Solo?) stem in the box. I was so excited when I first got it, I pretty much pulled out only unpacked the parts I needed.
If I remember to do so, I'll take some pictures of the leftovers. Some of them turned out really crispy, others are a nice golden colour. Kinda like some kinds of tobacco I think? Tobacco isn't my area of expertise though.
Just used the longer stem again at higher temperatures, and boy, does having the longer glass pathway make a huge difference! It makes it taste so much better when the vapor is cooler. At least, that's my experience. I find letting it heat up for a minute or so before I draw tends to help too. I need to learn how to store my herb -- I have it sealed in a crummy ziploc, and will hopefully invest in some of those Jyarz (or whatever they're called) in the near future.