> we do use data sources that plug into the booking systems for the flights, so it's not just a historical thing
Yes, I know exactly where you are getting the data. Your OTA API is a booking system that is intended to provide basic information to travel agents. You'll be presented with an IATA equipment code, or more likely the intermediary providing you the API is expanding it to an airframe or using ADSB data to supplement the field (as I mentioned up thread). The data field exists mostly for wake classification and general seating guidance.
You'll notice despite huge consumer demand none of the major booking sites rolled out an airframe filter. Booking Holdings put it on their metasearch site Kayak.com, but didn't deploy it on their direct sites like Booking.com and Priceline.com.
> I figure presenting info that has a high probability of being correct
The accuracy is inversely related to peoples desire for the information. When the MAX aircraft are grounded for example, you'll have massive fleet shuffles and the booking system does not get updated.
It is like advertising that you have a 100% accurate earthquake predictor (except when an earthquake happens).