Leave the TSA and the airliners to focus on the "items" terrorists would use on flights, inanimate objects, and fail to scrutinize those who human beings, who might carry out such acts, and who generally and commonly fit the criminal profile of the type of people AROUND THE WORLD causing this carnage everywhere. Then, we passengers, ought to make it our business to start questioning young, single, Muslim Arabic males who look suspicious, in line at security, in the passenger lounge, boarding bridge, in the cabin, everywhere. Where you are going today? What's your line of business? Where do you live? What country are you from? Do you speak Arabic? What book is that you are reading? Etc Etc. Examine everything about them, eye them up and down, if they get uncomfortable with it, tough luck. And finally, if suspicious people are allowed to fly, I mean the women in a complete black burqa with only a slit for eyes, then I'd get a group of passengers to protest and leave the plane if called for. PC things in the US will not change until they are overthrown from the ground up, at the grassroots, across the land.
Actually, while the scruffy, furtive, manic terrorist stereotype does exist (i.e., the shoe bomber guy) they are usually well-groomed, well-spoken, and well-behaved, which is why they succeed to the extent that they do. It's not as if they live in some bizarro alternative reality where they don't recognize what kind of behavior and demeanor is likely to arouse suspicion..
But, granted, there is the occasional imbecile nutjob exception, like that shoe bomber guy (I forget his name). Oh, and Moussaui also. But, hey, you might note that the exceptions are the ones that - surprise! surprise! - actually got caught before they did whatever it is they were gonna do.