The older couple from Hybla Valley drove their 2008 Scion into the underground parking garage at 8270 Greensboro Drive about 11 a.m. Thursday.
The car was proceeding slowly down the inclined ramp when it "picked up speed and went airborne," Phillip Graham, the parking attendant, said Friday.
The car traveled about 225 feet down the narrow ramp until it hit a concrete pole and a parked car at the end of the ramp, Fairfax County police said.
Graham said he called the police and EMT's from the Fairfax County fire and rescue arrived in less than five minutes.
Inside the car were Sumiko Hagan, 81, of the 7400 block of Northrop Road in Hybla Valley and Joseph Michael Hagan, 89, her husband and the driver of the car, police said.
Mrs. Hagen died at Inova Fairfax Hospital shortly after the Thursday morning accident, police said. Her husband died later at the hospital of the injuries he had suffered, police said.
Police released no information about why the Hagans had come to Tysons Corner. The building includes a gym often used by older exercisers, Cardinal Bank and mostly law offices.
Police said the investigation is continuing into the accident.
Graham, who lives in Hyattsville, Md., said he has worked for Standard Parking, which operates the underground garage, for two years but it was his first day at the Tysons Corner location.
"It was all too much to take in at one time," he said Friday afternoon.