Nadech and Yaya are Competitors
We are used to seeing both Nadech and Yaya working together within the same companies. But Yaya just signed with Bangkok Airways as their first ambassador this February of 2015. As for Nadech, he "has for several years been singing the praises of Thai AirAsia, starring in TV commercials for the low-cost airline and appearing at its public events," according to an article on nationmultimedia.com.
Yaya was interviewed and said that she didn't think it would be a problem that they are competitors, because they are competing for different markets anyway.
What do you guys think? If you were to go to Thailand, which airlines would you choose and does it have anything to do with who the ambassadors are?