I don't know, 'cos I have no WoW planes, but I'd guess they're actually resin. That's what most "hard" minis seem to be these days. All the Konami, F-Toys, Furuta and so on, they're all resin.
Speakin' of resin: this has absolutely zero to do with X-Wing but I'm so excited I gotta tell somebody! I just won a resin kit of the STAR FORGE off eBay. The Star Forge!! I couldn't believe it!! I had no idea such a kit even existed - found it utterly by accident. 110 mm (4 5/16") high, four pieces. Easy and incredibly fun!

