Tradesmen are or were indentured. You or your guardian signed to say that you would work for a set period of time, usually four years, for apprentice wages. These wages were a percentage of tradesman wages and increased each year. In return for your indenture, the company provided everything, tools, work clothes and paid for the apprentice to attend trade school. At no time was the apprentice ever asked to put his hand in his pocket. The apprentice could not belong to a union or go on strike. He could not leave his employer nor could he be sacked without mutual agreement and sitting before a Government tribunal.
Airlines want it both ways. They want to treat their so called cadets as apprentices whilst making them pay for the privilege.