MONTGOMERY, Ala -

 A woman and two of her sons were improving Sunday after being seriously injured when a flight information billboard fell on them at an airport.

   A third son was killed Friday when the electronic board, weighing at least 300 pounds, fell from a wall at the Birmingham-Shuttlesworth International Airport.

   The boys' mother, Heather Bresette, had broken ankles and a crushed pelvis. She had surgeries over the weekend, but she was still in intensive care and unconscious, University Hospital spokeswoman Nicole Wyatt said.

   "She does not know that her baby is dead," the family's priest, the Rev. Don Farnan, said. The Bresettes, a family of seven, took a weeklong vacation to Destin, Fla., and were about to fly home to Overland Park, Kan., when the arrival-departure sign fell.

   Luke Bresette, 10, was killed. His brother, 5-year-old Tyler, suffered a concussion. His 8-year-old brother, Sam, had a broken leg and nose. Tyler was let out of a children's hospital Sunday.

   Luke was the middle child of the five. The father, Ryan Bresette, and another son and daughter, were at the airport but not injured. During their vacation, the family swam in the Gulf of Mexico and Luke went parasailing for the first time.

   "His dad said he was thrilled. He was an adventurous kid. He loved sports," said Farnan, a priest at St. Thomas More in Kansas City, Mo.

   After the sign fell, it took six people to lift the large board and a dozen people to hold it up while first responders administered aid. Officials were investigating how the sign fell at the newly renovated airport and took down an identical billboard on Saturday.

   The renovated concourse opened March 13. It was part of an ongoing $200 million upgrade of Birmingham's airport