(CNN) -- Security measures and airline agents didn't prevent an 80-year-old woman from boarding the wrong plane.
Nefissa Yesuf, who was scheduled to fly from Atlanta to Dulles Airport in Chantilly, Virginia, on Sunday, allegedly received someone else's boarding pass from a Delta Air Lines employee.
She landed in Charlotte, North Carolina, after airline and airport employees failed to catch the mix-up.
"We got a phone call at 4:30 from the airport saying, 'Your grandmother was in baggage claim. Where are you guys?' " Melika Adem, her granddaughter, told CNN affiliate WUSA 9. "She was crying."
Adem told WUSA that Delta gave her grandmother someone else's ticket. An airline employee wheeled Yesuf through security in a wheelchair with the wrong ticket, WUSA reported.
Transportation Security Administration representative Greg Soule said circumstances surrounding Yesuf's screening are under investigation.
"Every day TSA screens nearly 2 million passengers and utilizes many layers of security to keep our nation's transportation systems secure," he said. "Every passenger passes through multiple layers of security to include thorough screening at the checkpoint."
Screening requires TSA officers to match boarding passes with a traveler's driver's license or other photo identification.
Delta is also investigating how Yesuf inadvertently slipped through the system, an airline representative said.
She reunited with her granddaughter Sunday evening.