Each year in the US 1 out of 6800 drivers dies in an auto accident. The rate for airline passengers is 1 in 1.6 million.

http://www.newton.dep.anl.gov/askasc...9/gen99845.htm

There were 733,908,000 "Revenue Passenger Enplanements" 6-2004 to 5-2005

http://www.bts.gov/xml/air_traffic/s...veMonthsSystem

733,908,000 / 3000 = 244,636

So, if 3000 people had been killed in this plot, then

Approximately 1 out of every 244,636 airline passengers would have been killed in 2006 (based on 2004-2005 enplanements).

1 out of every 6800 automobile drivers/passengers is killed.

As usual, we are emphasizing the wrong threat.