The reports of 'cigarette lighters' came from the cellphone calls on UA93 (see <a href="http://usinfo.state.gov/products/pubs/terrornet/print/sbhijack.htm" target="_blank">http://usinfo.state.gov/products/pubs/terrornet/print/sbhijack.htm</a> ). The passengers were obviously extremely distressed and few would have had a close view of the weapons. If unfamiliar with boxcutters, the Pacific brand looks almost exactly like a Zippo, and even makes a similar sound when opened.. .. .Show me some definitive proof of lighter knives and I'll willingly retract, but there are enough wild theories about that terrible day without perpetuating another.