It's not pluralisation, it's Asia. "Would you like fruits?"
Flap, flaps, same deal.
Or the casual statement as the runway goes under the nose, "Would you like some flaps, horse??" Simply implying more than One, and that 30 would be a good idea...
I was always a fan of the captain who carried a US quarter in his nav bag. Whenever the conversation turned to these nit picking ideas, he offered it to the guilty party to go phone someone who gave a f**k. And he was T&C