I did a search for aac and cut ... but that that returned too many false positive to know if this has been asked.
I am looking for a program like mp3DirectCut (http://mpesch3.de/) that does non-destructive (non re-encode) edits of AAC files.
Have a look at MP4Box (http://kurtnoise.free.fr/mp4tools/) (there is also a GUI (http://yamb.unite-video.com)) but if your files are tagged, this tool will remove them.
mp3DirectCut added AAC support a few months ago. See here (http://sergey.marechek.com/blog/2012/07/15/241/) for details.