kev, best thing is to just google the etymotics. They are simply 'ipod' type headphones of the flavour you stuff in your ear. What's 'special' is that they're designed to block out outside noise, and do so very well.
They would however be standalone - you'd put hour regular headset over the top, and plug the ipod headphones and the mic into the aeroplane, leaving the headset 'speaker' part unplugged. Not sure how I'd feel about the extra cabling etc. Of course this won't help at all if the mic is 'open' and the noise is coming through the mic!
I've not flown a tiger to judge, but I suspect the leather helmet or proper bone dome, coupled with decent headset/earcups (I use DC 10.14s), and the earplugs trick might be the most appropriate way forward.