T-vasis, your comment regarding Jetstar returning 6-8% would mean a lot more if anyone had any faith in the actual financial reports Qantas feed the public. You only need to read of the recent revelations about Jetconnect the 'company' to realise these figures cannot be trusted.
Anyone who has worked in Qantas for any length of time could give you many examples of mainline subsidising Jetstar since their inception.