Elf,
Right now, I'd say they have improved "airport security" over what it was before. It was almost "absent without leave" before 9/11.
Most of the improvements, however, have come in the area of searching and ID'ing passengers. I presently agree with the President of JetBlue who says the real problem is now "beneath the wing".
In short, Fuelers, Caterers, Aircraft Cleaners... these are all "contracted out" services now. Rarely do these folks work for an actual airline. Instead they work for the subcontractor who can supply an adequate "decent" (note: not flawless) service for the cheapest possible price.
Now, like the subcontracted Airport Security people, who do you think you get for the lowest possible price? What kind of security screening of these "lowest possible price" workers do we get when we pay the "lowest possible price"?
If I were interested in wreaking havoc on an aircraft now, I'd simply infiltrate my "martyrs" into one of these organizations and have them plant explosives or damage aircraft components. It would take some thinking and planning but the odds of them getting caught would favor my plan, I think.
As for inflight... the number of Air Marshals stuff.. there still isn't any "inflight security" and there never will be because we can't afford to put that many Air Marshals out there. You've got pilots willing to undergo similar training (based on defending the cockpit as a last resort) and pay for it themselves and do it on their own time. However, the Bush administration is opposed to that and it isn't going to happen.
So, you're left with a very few Air Marshals (relatively); instead they offer you a "better cockpit door". Whatever.
Anyway, that's my current .02 at present.