There are a few suggested solutions, like respringing, rebooting, hard reset, respring twice, whatever.
Or download Cydia tweaks such as iCache or white icon fix or fix white icons, etc.
In my experience, none of these work 100% of the time and I have tried all of them, on iOS 5.0.1 and 5.1.1.
The only thing that works 100% of the time, is going into Cydia, and installing a new package, or reinstalling a package you already have installed. I usually just re-install the Airplane sbsettings toggle because it's one of the first packages that show up when I go to manage-> packages.