I'm new to this board, but I have a few very worrying thoughts.
1) Couldn't a baggage handler or tarmac worker just waltz up to a plane and put a bomb on it, while nobody's looking?
2) What about cleaners?
3) Are there any security measures in place against (1) and (2) occurring?
4) Of the tentative candidates in the 2008 election (McCain, Giuliani, Feingold, Clinton, etc.), who do you think would enact the best policies to prevent (1) and (2)?
Sorry, don't have answers to your questions, but please just live and do not think too much about these things, there really is no use.
Breathing will mean that you die....eventually
It is all possible. You could also be hit by a meteorite when you pass your doorstep.
I don't know for sure, but the fact that all terrorist attacks on plane I know have been committed by people checking in through security suggests that there are security measures in place. And looking at the current stringent security measures I'd imagine they'd be even stricter for personnel having access to planes in the first place.
And as a fact, the likelyhood that you get hit by a car is a couple of thousands times higher (at least) than falling victim to a terrorist attack. And I don't hear people saying 'Oh, I won't get into a car, I could have an accident'.