Retired NASCAR driver Greg Biffle was not flying his own jet when it crashed last month, killing him and six others, according to a Friday report from investigators.

NASCAR legend Greg Biffle was not flying his jet when it crashed last month, killing him and six others.

Aviation safety consultant Jeff Guzzetti, who used to investigate crashes for both the NTSB and Federal Aviation Administration, said he believes the lack of an experienced copilot may have been a key...