A Russian oil baron who had six children – all girls – began to despair because he had no son and heir. Imagine his joy when one of his wives finally presented him with a son. Just before the boy's sixth birthday, the baron took him to one side and said: "Son, I am very proud of you. Anything you want, I shall get for you." The son replied: "Daddy, I would like to have my own airplane." Not wanting to do anything by halves, his father bought him United Airlines. Just before his son's seventh bir…