The Biffles were on their way to Florida for a birthday vacation, Cristina's mom Cathy Grossu told People, when their Cessna Citation jet crashed onto the runway while trying to land around 10:15 a.m.
"To think that they would be killed on a birthday trip, that was just such a fun time for the family," she told the outlet. "And to see the horrific way that it ended, it's just, it is so hard to bear. I cannot believe they're gone."
Cathy last heard from her daughter only moments before the collision.
"She texted me from the plane and she said, 'We're in trouble.' And that was it," Cathy said through tears. "We're devastated. We're brokenhearted."
In addition to the Biffle family, Dennis Dutton, Jack Dutton and Craig Wadsworth also perished in the accident, the cause of which is still under investigation.
"Dennis Dutton and his son Jack were deeply loved as well, and their loss is felt by all who knew them," the Biffle, Grossu, Dutton and Lunders families said in the joint statement. "Craig Wadsworth was beloved by many in the NASCAR community and will be missed by those who knew him. Each of them meant everything to us, and their absence leaves an immeasurable void in our lives."
"We ask for privacy, compassion and understanding as we grieve and begin to process this unimaginable loss," they continued. "We are grateful for the kindness and support that has been extended to our families during this incredibly difficult time. At this moment, our focus is on honoring their lives and supporting one another.”
Look back on more of the Biffles' family memories.
The driver made sure to share his love of racing with his kids.
Greg took his foot off the gas and slipped it into a dress shoe for a father-daughter dance with Emma.
In addition to racing, Greg instilled a love of fishing in Ryder.
The racecar driver and Cristina took advantage of every moment together.
Greg and Cristina celebrated Ryder's 5th birthday with balloons and, of course, some new racecars.
Greg never shied away from showing off his and Cristina's date nights.
When Greg was inducted into the North Carolina Auto Racing Hall of Fame, his family were by his side to celebrate.
