Praise be to Allah.
It is not permissible for a Muslim to imitate the kuffaar in his dress. If wearing these caps or anything else is one of their distinguishing features and something for which they are well are known and by which they are distinguished from others, then it is not permissible for the Muslim to wear those things. But if it serves some purpose and it is not something that belongs exclusively to the kuffaar, such as hats worn for work on building sites or in other workplaces, which are worn to protect the head and shade the eyes from the sun, there is nothing wrong with doing that. But if the hat is worn with the visor to the side or the back, this is not appropriate for the Muslim youth.