A creature like the Bloodkiss beholder hovers and flies 6.
If a rogue knocks this creature prone with a jumping blade assault, does the creature still have to stand?
Does knocking a flying or prone creature prone force them to waste a movement action standing before they can fly again?
If a prone flying creature does not stand, must it crawl?
Best Answer
If a flying creature takes falling damage from the fall due to being knocked prone, it is prone on the ground, otherwise it lands safely.
Prone:
Therefore, flying creatures fall.
Flying:
Therefore, a flying creature may or may not be prone, depending if it takes damage.
Crashing:
Therefore, if a flying creature is knocked prone at a distance of more than its fly speed, it takes damage and is knocked prone at the end of its fall. If a flying creature is knocked prone at a distance of less than its fly speed, it is merely grounded until it can take off again (provoking attacks of opportunity as appropriate.)
As a curious note, inflicting the "slowed" condition on a flying creature before knocking them prone is an excellent way of causing them both falling damage and being prone at the end of the fall, as the slowed condition reduces their speed.
The only movement allowed a prone creature is crawling, teleportation, or forced movement:
Therefore, a prone creature cannot fly.
Hover may prevent a creature from falling prone, but only from inference
Fly Speed:
Hover:
There is an argument to be made that knocked prone is countered by hover due to hover also countering stunned. It is not present in the rules however.
A creature hovering or flying one square off the ground with a fly speed of more than 1 lands safely when knocked prone, and therefore does not take falling damage. The lack of falling damage means that the creature is then not prone.
A creature flying at ground level is still in the "flying" mode of operation. and there are no minimum altitude rules. It can be assumed that a creature with hover will be flying at all times, and a creature with flight but without hover will be flying whenever there is little chance of being stunned or when its fly speed is greater than its ground speed.