Singapore Airlines give a lovely little note with your meal on flights in and out of Australia. The note says:
On flights to certain destinations, we are obliged to use plastic cutlery onboard, in accordance with directives from the local authorities. Thank you for your understanding in this matter. Have a pleasant flight and Bon Appetit!
This is, of course, to justify the plastic knife, fork and spoon provided with the meal. Mind you, when you are flying into and out of airports other than an Australian one the airlines provide metal cutlery (er, yes, and the UK and the US – plastic there as well I’d expect). Some airlines flying in and out of Australia provide metal forks and spoons and a plastic knife – which seems even sillier really.
The problem with all this security is that it really doesn’t make any difference to security. In Sydney, for example, checks on what passengers are carrying are made after emigration and well before boarding the aircraft. Whilst the cafes and such inside the airport provide plastic knives for eating as well there are so many other things that can be used in the airport (including used by the shopkeepers) as weapons.
I do have to wonder how much more dangerous a metal bread and butter knife is compared to a hard plastic serrated edge knife? I really think the plastic knife is just for show.