It will come as a surprise to many people, but it's quite possible to lose a ton of money on a toxic client who is paying you millions. Avoid such "white elephant" clients at any cost. And really, the last thing you need in your life is getting dragged into some huge conglomerate's internal politics.
I never worked with Singapore Airlines, but people who have experience with them tell me they're even worse in the sense that they allegedly have a policy of not paying for software - you get to give them free stuff in exchange for being able to list them as a client. Huge software companies can afford to do that; your growth stage startup probably can't.