The 787 flies almost exclusively to Band 5 overseas ports (USA/UK/HKG) which pay 295 AUD per day tax free - the 747 flies to many more countries not in band 5.
Why is that relevant? The allowance rates paid are dependent on:
a. the places one is put by the company,
b. the time spent in these places, and
c. determined by the Australian Public Service rates for those places,
d. as
agreed by Qantas in the Enterprise Agreements.
Allowances are
not income; they are intended to cover the reasonable, and independently assessed, costs of staying in those places. (but, granted, if a person chooses to stay in their room & live on cup-noodles they’ll have funds left over.
) If crew don’t travel they don’t get allowances. Allowances are a business cost of having crew serving your company’s customers around the world.
I disagree that allowances should be considered part of an employee’s income.