Is the Perfect, Untraceable Murder Possible?

I believe I created a perfect murder for my newly reissued novel STALKING THE SKY.  And not just the murder of one person, but of over three hundred.  And I did it twice.

STALKING THE SKY is the story of America's leading airline in crisis.  As a ruthless corporate raider is moving to seize it from its legendary founder, one of its 747s explodes in mid-air, killing everyone on board.  Then a second airliner goes down.  Sabotage is suspected.  Will Nye, the airline's general counsel who lost his best friend in the second disaster, is working closely with the FBI to track down the killer.

Obviously a bomb of some sort had to be employed with the killer able to escape after placing it, but how to accomplish that and how does one place it in the absolutely precise place to disable a giant aircraft built to survive a multitude of in-air mishaps?  I devised a scheme, but needed to be sure my scheme would work.  On a vacation trip with my wife, I entered the jetliner's lavatory and nervously went through enough of the steps my murderer would be taking to place the bomb until I was sure that I—and he—could get away with the crime.  Fearing arrest at any moment, I returned, sweating, to my seat.  Yet, like the murderer, I safely got off the plane at my destination.

A perfect mass murder?  I think it would have been.  I'll leave for my book's readers the details of how one gets a bomb on board and still makes a safe getaway.  But I'm sure that if Will hadn't found and tracked down a tiny clue I planted, STALKING THE SKY would have had a very different ending: The killer dancing all the way to a happy and very wealthy retirement.

So, I definitely think a smart, thorough thriller/mystery writer could devise a perfect plan to get away with murder.  The question is: How many novelists pecking out their daydreamed plots possess a killer's nerve?