Qantas has dumped Linux in favour of IBM's AIX flavour of Unix. The move is part of the airline's eQ transformation project and is designed to create a more stable system.
According to ZDNet the move bucks the trend in the airline industry away from AIX, HP/UX and Solaris to Linux.
The eQ program in general is designed to deliver more efficient
information for the airline and will be based around Oracle's 11i
database and applications, ZDNet quoted Qantas as saying that AIX was
much more stable for the project than Linux could manage.
You can read more here