What is the difference between Istisna and Ijarah?

According to Istisna, the manufacturer either uses his own material or he arranges for the material himself whereas under Ijara the material is provided by the customer and the producer uses only his labour and skill meaning that his services will be hired for  a specified fee paid to him. Further, under Istisna the purchaser has the right to reject the goods after inspection if these are not according to the specifications agreed at the time of contract whereas under Ijara this right of examination does not exist.