Oracle Linux is an Oracle Production.
AIX 6.1 is an IBM product
Q: Like Oracle Linux, can we download Oracle AIX 6.1 operating system download from Oracle.
A: No. You need to contact your OS vendor for this.
Oracle Linux is an open source operating system available under the GNU General Public License (GPL) and other open source licenses. It is available for free download
Note: Oracle offers 24x7, global support for Oracle Linux through a paid subscription.
for more info on "Oracle Linux" you can refer below URL