FWIW, WhatsApp does (or did) support special price networking. I used to be the engineering side of that. But the supported offerrings were for special priced everything (text+mms+voip) or just text+mms if real time voice and video was not to be special priced. Text only was not a supported offering while I was there. And you needed to be a mobile carrier to get the information about IP ranges (the IP ranges were public but not directly linked early on, but got limited later).
That said, many networks did these sorts of things without communicating with WhatsApp. Even without knowing IP ranges. WA traffic is easy to spot. Chat has a destinctive protocol that's neither http, nor https; mms is https with obvious hostnames in SNI; voip looks like voip.
You might be able to trick in-air wifi by looking like WA chat, but I've never been interested enough to check while on a plane. I'd rather use the time to watch awful movies on a tiny screen with terrible audio conditions.
That said, many networks did these sorts of things without communicating with WhatsApp. Even without knowing IP ranges. WA traffic is easy to spot. Chat has a destinctive protocol that's neither http, nor https; mms is https with obvious hostnames in SNI; voip looks like voip.
You might be able to trick in-air wifi by looking like WA chat, but I've never been interested enough to check while on a plane. I'd rather use the time to watch awful movies on a tiny screen with terrible audio conditions.