Complex sentence: All Walsh brothers flying boats had been made for the use of the school, not for sale, and were transferred to the NZPAF; however, the NZPAF had a landplane training programme based upon the Avro 504K and had no use for the flying boats.
Split into simpler sentences: All Walsh brothers flying boats had been made for the use of the school, not for sale. The NZPAF had a landplane based training programme using the Avro 504K and had no use for the flying boats.