Is the saxophone easy to learn after you already know how to play the flute?

I might be joining marching band soon and I already have been playing the flute for longer 3 years. But I can’t play flute in the marching band and I don’t want to play the picccolo, so I was wondering if it would be a lot of hard work to learn how to play the saxophone. If it is, does anyone know if any other marching instruments might be easy to learn other than the piccolo?
Thanxz!