Beautiful widget plane mode does not put the device into airplane mode. It disables wifi and bluetooth but that is all.
I tried reporting this on IRC, in the 126.96.36.199 threads here and on cyanogenmod forums.
Is there a better place to report bugs? Apologies, I'm new to the cyanogenmod community, as it were.
Update: found out over at cyanogenmod forums that koush is aware of the issue.