prudent deployment of cash flows. Driving Revenue Growth

Operational Reliability

A key driver of our revenue growth is higher customer satisfaction resulting from strong operational reliability. We have significantly invested in our business since 2010 to improve our operational performance, which consistently ranks first among the major U.S. carriers. During 2015, we operated 161 days with zero mainline canceled flights, a 69% improvement over our 2014 performance. In addition, our reported completion factor of 99.6% and on-time arrival rate of 85.9% places us at the top among the major global U.S. carriers. This operational excellence resulted in a four point increase in our domestic net promoter score compared to 2014. Accordingly, our corporate ticket volume increased 4% in 2015, reflecting our reliable service and high-quality product.

Global Strategy

We are expanding our global network. Under this strategy, we are strengthening our presence in major and developing markets around the world in an effort to increase and diversify our network into high revenue and high growth markets. The growth of our global presence will enable customers to seamlessly connect to more places while enjoying a consistent, high-quality travel experience. We are deploying this strategy through investments in Europe, Asia and Latin America.

Europe. Alongside our 49% equity investment in Virgin Atlantic, we implemented an antitrust immunized joint venture with the U.K.-based carrier. This joint venture has significantly improved our presence in London, one of the largest revenue markets from the U.S., while also enhancing our transatlantic network including our existing joint venture relationship with Air France-KLM and Alitalia. We have also moved senior decision-making functions to Amsterdam for closer coordination with our joint venture airlines. We anticipate the co-location of these management functions will optimize the benefits of our joint ventures.

Asia. As part of the strategy to improve our Pacific operations, we are increasing our presence in China, the largest transpacific market from the U.S. To this end, during 2015, we acquired shares of China Eastern for $450 million, which provides us with a 3.5% stake in the airline. In conjunction with this transaction, we and China Eastern entered into a new commercial agreement to expand our relationship and better connect the networks of the two airlines. China Eastern is one of the largest airlines in China with a route network covering more than 200 destinations in over 25 countries. In addition, we are restructuring our Pacific fleet by removing less efficient B-747-400 aircraft and replacing them with smaller-gauge, widebody aircraft to better match capacity with demand in an effort to improve our margins.

Latin America. We are focused on maximizing the value of our relationships while deriving value from the recent investments in our network, product and service. Our capacity growth has been focused on higher performing markets such as Mexico and the Caribbean, while we have reduced capacity in markets challenged by weakening currencies and slowing economies such as Brazil.

During the