Creature with fly speed (no hover) and falling?

Are there any established rules about flying creatures without hover mechanics when it comes to falling?

Example, a pitfall trap opens under an Owlin.

Do they subtract their flight speed from the distance they fall before damage is calculated?  If they used any movement on their previous "turn" does that impact calculation? 

Quote from MobiTraveler >>

Are there any established rules about flying creatures without hover mechanics when it comes to falling?

Example, a pitfall trap opens under an Owlin.

Do they subtract their flight speed from the distance they fall before damage is calculated?  If they used any movement on their previous "turn" does that impact calculation? 

No, none of that is in the rules.

Being able to fly without the ability to hover doesn't have any impact on falling.