If they were actually fair dinkum why would you waste your time trying to attack aircraft/airports? It totally illogical given the number of soft targets out there.
Au contraire. There's nothing to stop a few individuals from simultaneously walking into the main east coast terminals and up to a crowd at the screening point with a baggage trolley loaded full of stuff that goes bang. The subsequent loss of life, terror and economic damage would be unprecedented.
Explosive screening involving dogs and cops should occur well before anyone enters the terminal, in a quarantined area (car park) before being bussed to the terminal. Similarly people arriving by train should be sniffed before entering the terminal. Thereby reducing access to crowds and infrastructure.
No terrorist seeks to blow up a carpark.