Is it possible to install Windows 7 as a second OS on a Macbook Air with no access to a superdrive? And if it is, how?
I created a bootable USB stick with my Windows Vista DVD. I followed the instructions on Install Win 7 on MacBook Air from a USB drive.
The most straight forward method to actually getting this done is to get your hands on an external DVD drive that connects via USB but is not the point of your question.
Yes it is possible; you'll need to get your copy of Windows 7 DVD put onto a USB thumb drive. (There are several guides available online - I've not done it myself so I can't recommend one)
Another alternative requires a lot of extra work and is really designed if you're planning to image or install on multiple MacBook Airs; it's possible to NetBoot your MacBook Air using the USB Ethernet adapter. (Source) This requires either a rigged out version of Mac OS X or Mac OS X Server handy. With DeployStudio you can install a pre-made image of Windows 7 that way.
Even better way is to use VirtualBox to install windows or other OS on mac book. You can always delete it when you want. With a little loss in speed, you gain a lot.
I had blogged on how to install ubantu Linux with VirtualBox. Installing windows is no different.