The plane crashed at the Statesville Regional Airport in North Carolina.
The North Carolina Highway Patrol said it is believed that Biffle and members of his immediate family were among those killed but because of a severe post-crash fire a formal confirmation has not been completed. The plane was registered to a company tied to Biffle.
Officials will provide a list of the seven occupants once confirmation has been made by the medical examiner’s office.
The plane had been bound for Florida but soon after takeoff attempted to return to the North Carolina airport in severe weather around 10:15am local time. (15:15 GMT) according to FlightAware, an airplane tracking site.
A picture posted by local media and social media showed a large fire on the runway amid the plane wreckage. The National Transportation Safety Board is sending a go-team to the scene and will brief media on Friday on the investigation.
Biffle, 55, won 19 Cup Series races over 20 years, according to Field Level Media. His final race on the circuit was the 2022 Geico 500 at Talladega. He was named one of NASCAR’s 75 Greatest Drivers in 2023.
Republican Senator Thom Tillis of North Carolina was among lawmakers to eulogize Biffle. "Greg was a titan in the NASCAR community both on and off the racetrack," Tillis said.
"After Helene devastated Western North Carolina, Greg stepped up without hesitation by using his own personal helicopter to rescue victims and provide crucial aid to North Carolinians in need."
The airport was closed after the incident and the debris must be removed from the runway before it can reopen, city officials said at a press conference.