Singapore Airlines, the national carrier, updated its policy following the latest guidelines from the Singapore Government and drops general mask requirement on many routes,
Like most Asian airlines, Singapore Airlines strictly enforced the mask mandate onboard all its flights, regardless of destination, to stick with government guidelines. Any passenger aged six and above was required to wear a mask during a flight and was only allowed to remove the mask during meal times. However, the Singapore Government recently announced that mask-wearing would no longer be mandatory unless on public transport and healthcare facilities.

Singapore Airlines was voted Asia’s leading airline in the 2021 World Travel Awards - https://www.worldtravelawards.com/award-asias-leading-airline-2021

The welcoming news means that passengers flying on Singapore Airlines will not be required to wear masks on their flights from August 29th onwards unless they are flying to and from destinations that still mandate it. Mask wearing has also become optional at Singapore’s Changi International Airport, but passengers who still wish to wear a mask onboard or within the airport regardless of destination may continue to do so.
For its flights SQ25 and SQ26, Singapore Airlines requires a mask onboard due to Germany’s regulatory requirements. Due to Spain’s regulatory requirements, masks are also necessary onboard flights SQ377 and SQ378 between Milan and Barcelona. While it can be confusing with the updated policy, Singapore Airlines has provided a list of routes flown from Changi Airport:

With Singapore Airlines setting the precedence of scrapping the mask mandate, its low-cost subsidiary Scoot might soon follow suit. The budget airline may presumably make masks optional for flights to Greece, Japan, Saudi Arabia, Taiwan, and Thailand. Scoot might also follow in the primary carrier’s example of allowing the wearing of face masks optional on flights to Australia but making it mandatory on flights back to Singapore.

Though regardless of any airline’s mask policy, given how several countries still impose that mask-wearing be mandatory, it would still be best for passengers to pack a mask or two whenever and wherever they travel for the best avoidance of confusion.