In reply to mc2006:
But if you have unusual items it can slow you down. Recently, I was carrying some parts for a model aircraft including an engine in my hand luggage. At Houston airport this was x-rayed, hand-searched thoroughly, x-rayed again, hand-searched again, x-rayed for a third time, and then hand-searched for a third and final time, before I was allowed to proceed. Took about 20 minutes!