In February 2009, Continental Flight 3407 crashed into a house, killing all 49 people aboard and one person on the ground as the plane was arriving in Buffalo, New York. Since then, U.S. airlines have transported about 8 billion passengers without a single fatal crash.

"There's one dangerous part of the airplane trip, and that's the drive to the airport," said John Cox, a retired airline captain and an aviation accident investigator.

The fiery crash of the turboprop plane on Feb. 12, 2009, prompted federal regulations requiring more rest and training for pilots. In their investigation report, U.S. safety officials cited fatigue and the need for more training. They said pilot error was the probable cause as the plane lost speed and stalled a few miles from the airport in Buffalo during a flight from Newark, New Jersey.

In 2013, the Federal Aviation Administration increased the requirements for commercial pilots and first officers. They now must have 1,500 hours of flying experience before getting a commercial license. The previous requirement was 250 hours. Rest requirements for pilots were also increased following the crash of the plane, which was operated by now-defunct Colgan Air. The first officer of the Bombardier Q400 plane had taken a red-eye trip the night before from Seattle and then commuted from Memphis, Tennessee, to Newark before the flight to Buffalo, according to the accident report.

The captain of the plane had repeatedly failed flight tests throughout his training, drawing more scrutiny on pilot candidates' education.

"The life-saving changes that came out of that event have truly been profound," said National Transportation Safety Board Chairman Robert Sumwalt, who investigated the crash at the time.