Learning Curve Happy Flyer GymNow you can enjoy tummy time with your little one with the Happy Flyer Tummy Time Gym. Babies gently and comfortably spin around on their tummies, stretching and building their upper body. The Happy Flyer helps develop the physical skills and muscles for rolling over, sitting and crawling. Learning Curve has put a unique spin on tummy time play, an important developmental phase for all newborns. Age: birth - 6 months