Being paid overtime at a higher rate is compensation for:
1 the irregularity of when you receive it (overtime is by its nature unpredictable and at short notice)
2 inconvenience if you'd made other plans
It is also a reward for workers' loyalty and flexibility.
Would full time workers like to give up a 40hr/wk contract to go on to 20hr/wk and hope they get another 20hrs/wk overtime every week? Would that pay the mortgage? No, so that's why the full timers trade some overtime premium for a guaranteed income every week, to pay the bills.
I'm sure the airport lawyers will have agreed these contracts before they were issued.
Is this a non-issue? Is it just the airport unions rattling their sticks in the swill bucket again for some other agenda, perhaps to make themselves look like they're doing something? The airport unions have sadly been impotent for years.
Workers still come; management still treat them badly. Welcome to capitalism.
I would like to add, before you all rip my head off, that I have great sympathy with the poor wages, working conditions, welfare facilities etc. of the ops staff, as well as having to park miles away at 3am to get in for an early start, when the bigwigs park in undercover luxury and only have to waddle across the road to OH at 9am.