They claim on their Kickstarter that they can get around this:

The Apple Review process restrictions are very specific. Apple forbids the dynamic loading of remote code. But this is not what Air-Control does, our library contains all the code it needs so no code is loaded dynamically. Our library only downloads content and configurations, which is permitted by Apple.

For a very similar use case we can reference our existing tool, nativeCSS, which is a dynamic styling library for iOS and Android. This is very similar to what Air-Control does, it downloads styles and applies them to a running app. This has been installed in a wide range of Apps, and has been approved by Apple since its launch in December 2012.

Whether or not Apple actually goes for this is another question entirely.