Security on the ground and in the air has made vast improvements since 9/11. But would you book a flight? (Credit: Getty)

On the 12th anniversary of the terrorist attacks of Sept. 11, 2001, many Americans' thoughts turn to travel, aircraft security and TSA checkpoints.

But does this keep people from boarding planes?

Airline travel did dip in the years immediately following 9/11, but since 2005, the number of airline passengers has steadily increased, according to the most recent data from the U.S. Bureau of Transportation Statistics.

And airports are far from empty on 9/11, said John Nance, aviation analyst for ABC News.

"For the first five or six years following 9/11, the drop was true," said Nance. "But now it's mostly a mythology. There hasn't been anything for the past five or six years that indicates the possibility of another aerial attack on that date."

Nance also said that procedures at TSA checkpoints had markedly improved in the years since the attacks.

"There's no question that what we had passing as security before 9/11 was a sick joke," he said. "We had the absolute bottom-level employees, who couldn't even speak English in many cases, and who had a minimum amount of training working a job they didn't want to be doing. It was an idiotic system doomed to failure, and it was only a matter of time."

Even more crucial, Nance said, is the increase in aircraft security over the past 12 years.

"The No. 1 job in making sure 9/11 never happened again was denial of access to the cockpit, and we've done that," said Nance, referring to the reinforced doors and changed cabin drills that prevent intrusion. "The risk of having an airplane commandeered and used as a missile is pretty close to zero."

Still, for some, more than a decade and numerous security improvements have not diminished the emotions and fear surrounding air travel on the 11 th day of September

"Besides a couple of terrifying near misses involving a shoe bomber and liquid gels, there hasn't been a major incident or threat," blogged Rita Anya Nara, author of " The Anxious Traveler."

But she herself would not be flying that day. The date Sept. 11, she wrote, "still holds that sickening power of imagination and dread over us."