Head injuries do not always show up immediately. If you notice any neurological signs like trouble walking or balancing, appearing disoriented, vision issues or anything odd such as being overly sleepy, then you need to take him to an Avian Vet.
As for flying, it is great exercise for a pet bird. But if a bird lacks coordination or tends to fly into things, then a wing trim to slow him down can be a good idea. However, he is not doing this for no reason – most likely something is startling him. What you need to do first is try to figure out what is startling the bird and causing these frantic flights. Birds are prey animals, so they can get startled by anything that appears out of nowhere or comes from above or behind them. Is there a window near him? Any movement outside can spook a bird – another bird or a pet, a person, even a car driving by or foliage moving in the breeze. Someone suddenly walking into the room can startle a bird. A loud sound or a sound on TV can alarm a bird. You should always be in the same room with him when he is out of the cage. If you have been leaving the room, then he may feel insecure without you there. He may fly around because he is looking for you. But from what you describe, I think something spooks him and sends him into a frantic flight to escape danger. If this is the same bird you mentioned in the previous question, he may have vision issues from the last injury, in which case, you may have to keep him clipped for his own safety. The Vet can assess his vision.
Thank you for asking Lafeber,