This isn't the case depending on how new your MBA is, or what the specs are. Generally the top of the line MBA has way more then enough power to run a linux VM.
The huge downside is that I made the mistake of getting the 128gb option, which frankly is far too little. VM images, Photoshop, Office, and lots of little project files all take up a surprisingly large amount of space.
If you want to go for the MBA, get at least 256gb.
What CPU does yours have? I bought the i5 Haswell.