"I'm just starting to realize what I did," Maddison said. "Conditions weren't in my favor with the wind."
Maddison broke the Guinness World Records-certified mark of 277-6 set by Trigger Gumm in 2005 in Australia, and the non-certified mark of 310-4 set by Ryan Capes in Kent, Wash., also in 2005.
During practice Sunday night, Maddison jumped 350 feet. It was unclear if that jump would be certified as the record.
"We had terrific conditions," Maddison said of the practice jump.
On Monday night, Maddison landed in perfect control on both attempts, sailing over a drawn-in football field and coming down on a large dirt landing area.
He was asked how far he thinks he can jump.
"Four hundred feet," Maddison said. "I know I'm definitely going to do it."