I was wondering what an old Boeing 727 costs, and went checking out the ones for sale on the web.  They can be as cheap as $650,000 for freighters that are more than 30 years old.

Well, didn't I read somewhere that the 9/11 operation cost a total of $500,000?  Sure they hijacked the 4 jets which would have set back the Arab financers of 9/11 $2,000,000+ (less if they loaned the money) if they had bought old freighters and loaded up the cargo with extra fuel.  And sure the 9/11 hijacker pilots were dumbasses who barely mastered how to fly and manuever in flight, and flunked out of their training programs with only the bare minimum of skill needed to accomplish their mission.

What if they get it together enough to fully train another terrorist pilot, establish a front company and purchase a 727, load it up with fuel or ammonium nitrate and fly it suddenly into the Sears Tower?  No hijacking warnings, no chance of passengers re-taking control of the plane. No chance of being busted at the security gate with plastic knives. No pilots with handguns in the cockpit.

Eeeep.

I somewhat doubt they'll use the same tactic twice.  Maybe, but I doubt it.

NBC warfare is a whole heck of a lot scarier.

What if they load up a whole 727 with anthrax or botulism with a bursting charge, and detonate over NYC or San Francisco (very dense cities)

They could do the same thing with phosgene or chlorine gas.

Big Bear - the big 4 target list would likely be:

1} N.Y. ( they got round 1 )
2} L.A. and/or San Francisco
3} Chicago
4} Washington D.C. ( Hit but not as bad as the bad guys had hoped.)