U-FLY Alliance is the world's first alliance of low-cost carriers, formed in January 2016 between founding members HK Express, Lucky Air, Urumqi Air, and West Air. All four founding airlines are affiliated with the HNA Group, with a focus on Hong Kong, mainland China, and Southeast Asia.
The alliance was formed for various reasons. Since China’s provinces vary in what they allow and don’t allow for airlines it is difficult for two or more airlines from different regions to merge.
The alliance was formed to help smaller airlines grow larger without becoming one company in several different provinces. Another motivator for creating an alliance instead of merging is that the regions preferred to have a local airline with a local identity that can advocate for the area it is in. U-FLY Alliance was announced on 18 January 2016 at a press conference in Hong Kong.
In 2017, U-Fly Alliance partner’s capacity included over 44 million seats, touching 18 countries, 149 airports and 339 city pairs. With over 129 aircraft currently in operation.
According to en.wikipedia