Notarious is a bit off base, the three little bones are nice, but there is a lot of meat between the ear plugs and that stuff. The real problems are air pressure problems with some types of plugs and ear damage due to noise:
1) The plugs we all wear are the roll-up foam kind, which don't seal airtight, and thus allow pressure equalization. They cut ambient noise by 20 dB, and are very effective. Rubber airtight plugs are dangerous in aviation, as they can get pushed into your ears as you descend. The foam kind are issued like popcorn in aviation outfits around the world.
2) Noise reducing headsets might not protect your ears against the high frequency sounds that might be a problem, as the sound cancellation circuits are not very effective above about 1000 HZ, so damaging sound levels above frequency are still a problem, and must be blocked with well-sealed earcups and plugs. The active noise cancellation is great for comfort and clarity, however, and so are really popular around here.
Here is a simple plot at the web site of a company that sells ANC headsets:
http://www.sennheiserusa.com/pages/p...ctiveindex.htm
3) The best protection is a good set of well fitted earcups and a sound sealed headset/helmet. Plugs are an addition to this first step. A soft gel earcup is mandatory, and needs to be changed every few months.