The recent addition of "private sales" removed the ability to "transfer" aircraft and FBOs that you owned. Instead, you had to "sell them to yourself" for $1. The original transfer feature is being restored, but you may only transfer between your personal account and groups that you own. You still may not transfer assets to other players without using the "private sale" feature. Group staff members may not "transfer" assets.  Leased aircraft may still not be transfered. If you want to move a leased aircraft from your personal account to a group you own, you must arrange the transfer with the aircraft's true owner. 

(this change will be rolled out later today)