提高经济效益的主要方法是增加收入，降低成本，也就是人们常说的开源节流。通常开源受企业外部经营环境的影响较大，而节流水平的高低主要反映了企业内部的管理水平，邯钢的成功经验就是有利的证明。飞机的维修成本通常占直接营运成本的14％，这一部分是最有弹性的，也是人们? The main method to increase economic efficiency is to increase income and reduce costs, that is, people often say that the government increases revenue and reduces expenditure. Generally, the open source is greatly affected by the external business environment of the enterprise, while the level of the restriction mainly reflects the internal management level of the enterprise. The successful experience of Handan Iron and Steel is a favorable proof. Aircraft maintenance costs usually account for 14% of direct operating costs, this part is the most flexible, but also people?