The Transportation Security Administration has responded [1] to a CNN investigation [2], which reported [3]that fewer than 1 percent of flights daily have a federal air marshal on board, calling its federal air marshal program "highly successful."

On its Website, TSA set up a "myth buster" Web page devoted solely to debunking the specifics of CNN's report.

CNN claims there exists the possibility that less than 280 flights out of a daily 28,000 have a federal air marshal on-board, which TSA flatly denies.

While the exact number of flights that air marshals protect is classified because we don't want terrorists to play a mathematical guessing game based on percentages, the actual number of flights that air marshals cover is thousands per day. This represents exponentially more than 1 percent and is well into double digits.

TSA also says what matters most isn't the number of flights air marshals deploy on daily, but which planes air marshals board. TSA places air marshals on planes based on intelligence and risk. Anonymous sources CNN spoke to, however, claimed there is a lack of air marshal coverage on flights in-and-out of New York City and Washington, D.C., both cities that were hit in the terrorist attacks of 9-11.

The agency responded that CNN's reliance on anonymous experts, pilots, and air marshals was shoddy journalism because none of them have access to the global scheduling information.

Every single day of the year, air marshal schedules are altered to cover specific, high-threat flights. That means on one day, many flights into and out of New York and D.C. may be covered and on other days, less flights may be covered.

TSA also said CNN's claim that the air marshal program was hemorrhaging talent was wrong and that air marshal attrition rates of 6.5 percent a year is "comparable to other federal law enforcement agencies."

Over at its blog Evolution of Security [4], the TSA also clarified what the word "coverage" or "covered" mean. CNN reported that sources told it that TSA considers a flight covered "even if a marshal is not on board -- as long as a law enforcement officer or pilot in possession of a firearm is on board, even if that person is flying for personal reasons. The 'covered' designation includes pilots armed in the cockpit."

A TSA blog post says that is wrong:

To the uninitiated, “covered” means there’s an air marshal team onboard. We have been asked if this includes other armed federal, state and local law enforcement officers. The simple answer is no. To determine the number of flights we cover, we use only our air marshals.