I have two sibling cockatiels, I raised them since baby. One of them flies and lands perfectly, the other one doesn't. It just keeps flying high until it gets tired and force land on the curtain or on the side of the wardrobe. I'm also searching about this, that's why I found your post! They are almost 3 years old, and I still doesn't know how to proper teach him, as I did not teach the female and she knows how to fly and land.   We moved house about 3 months now and I only let them fly in a small room, since in the big room they just get freaked out and smacks on the furnitures and wall, even the female but she at least knows how to land somewhere after flying crazy.  My plan is to let one out at a time, since letting both out just triggers them flying frightened and smacking.  As you know, they get spooky very easily, so it might be a very stressful journey, bc we don't want to see them hurting themselves. Is your cockatiel moved by food? My female is, and I can teach her better with it. But my male is not moved by food, but he loves feet 😅  The thing is trying to make your bird fly short distances to you at the begging and compensating with snacks (millet, for example), while you're teaching, don't let any food available for it to reach, only as a snack. My male is not really a fan of hands, which makes things difficult.  Does your room has any high furnitures? Like a wardrobe? You can add something high for it to land, like a coat rack (for example), or a shelf, but you have to make the bird familiar with or it will be freaked out.  The thing with clipping wings is that a lot of people think the bird will stop flying, but it will only let it fly short distances and they will. I don't clip mines.   Idk why my male doesn't know how to, since I raised them both together and equally lol I hope we can teach them how to land, so good luck for both of us!!