The Frenchwoman soared into the lead on qualifying day at the FIS Snowboard and Freestyle Ski World Championships in Aspen, hitting a 95.00 to lead Italy's Silvia Bertagna (94.00) and Anastasia Tatalina (93.25).
"It’s a perfect day," 18-year-old Ledeux told FIS after her qualification jumps. "We have a lot of chance with the weather. The jump is just amazing. I am very proud of me because I didn’t ski during two months before coming here so I am so happy to land these tricks."
The men's and women's freeski Big Air finals will take place on Tuesday, followed by the snowboard Big Air final later in the day.
Norway's Birk Ruud, a two-time X Games Big Air champ and the 2016 Youth Olympic Games gold medallist in freeski slopestyle, leads the men.
The top 12 men and top eight women have qualified for Tuesday's final, including Gu Ailing Eileen, the Chinese teenager who has already captured gold medals in both the freeski halfpipe and slopestyle, making her the first freeski athlete to win multiple golds at worlds.
Ruud: 'I am in a good position'
Ruud is looking to make his first big mark at worlds, having won Big Air X Games golds in both 2018 and 2019, as well as a pair of silvers in 2020. Ruud had a big start to the 2021 season, winning the first FIS World Cup in freeski Big Air in Austria, landing two 1800s in his first two jumps.
"I am very happy to put down my first run and I am in a good position so hopefully I make it the finals," Ruud told FIS on Monday. "And looking forward to tomorrow. Perfect day for it."
Switzerland's Andri Ragettli has also qualified for the final, having already collected gold in the men's freeski slopestyle. The aforementioned Hall, the American, won bronze in the same event.
Canada's Megan Oldham is also looking to add to her medal haul from worlds: She won bronze in the women's freeski slopestyle behind Gu and has also launched her way into the Big Air final.