BEIJING/SINGAPORE (Reuters) – Xia Lili, marketing chief at a privately-owned Shanghai software firm switched to flying with Spring Airlines after China’s first low-cost carrier took off in 2010. Xia and her colleagues are among an increasing number of Chinese who are fuelling fast growth in what is often called the “last” big market ripe for low-cost carrier penetration. Since late 2013, the Civil Aviation Administration of China has encouraged budget airlines as Beijing has seen how they have taken off elsewhere.