Ну есть же рулбук, в конце концов:
"Flyers have flying bases that suspend them above the battlefield. However, distances are still measured to and from the Flyer's hull, with the exceptions of the vehicle's weapons and Fire Points, which all work as normal. The base of a Flyer is effectively ignored, except for when:
- The Flyer is being assaulted, in which case models may move into contact with the vehicle's hull, its base or both.
- Models are embarking or disembarking from the Flyer, in which case the base of the Flyeris used as the Access Point."
Исключения, типа того же Дыроконя, прописаны отдельно.