Most software that runs on Linux can run on FreeBSD using an optional built-in compatibility layer. AIX is based on UNIX System V with BSD-compatible extensions. Is there a Linux compatibility layer in IBM AIX?
If you're thinking about running Linux binaries directly on AIX, then no there is no such feature (even if you can find binaries for the Power architecture for the Linux software you're trying to use).
IBM does provide something called the AIX Toolbox for Linux Applications which should help porting software developed for Linux to AIX. It is a collection of tools and libraries usually found on Linux including GCC, Gnome and KDE, and a bunch of libraries and tools (gawk, bash, ncurses, rsync, lsof, ...). But you'll have to recompile:
Because Linux and AIX use different Application Binary Interfaces (ABIs) (like Linux on different hardware platforms uses different ABIs), there is in general no binary compatibility when changing operating systems or hardware architectures. For example:
Linux applications that have been compiled under Linux on hardware other than IBM pSeries or IBM iSeries can in general not run under Linux for pSeries without recompilation.
Linux applications that have been compiled under Linux for pSeries cannot run under AIX, including the AIX Toolbox for Linux Applications.
Linux applications that have been compiled under AIX using the AIX Toolbox for Linux Applications cannot run under Linux for pSeries.