sooooo this happened when I first attempted to load into IAH... Midway through loading, several of these warnings popped up.
FSDT_KIAH_T1A.mdl (with different letters at the end)
This is the very first time trying to use this airport. The product is active within the addon manager.
I'm using P3Dv3 and I have reinstalled a few times and added and unloaded the scenery in the scenery library.