Spelljammer Spell Jammer speed

[Evilhalfling]

can creatures attain spelljammer speeds?
clearly beholders need ships.

But is it case by case or blanket for all flyers? kindori (space wales) murder comments and lunar solar dragons seem like good candidates.
I cant even tell what was happening in 2e.

 

[Ferrousbones]

can creatures attain spelljammer speeds?
clearly beholders need ships.

But is it case by case or blanket for all flyers? kindori (space wales) murder comments and lunar solar dragons seem like good candidates.
I cant even tell what was happening in 2e.

I am fairly unfamiliar with pre-5e Spelljammer, but I remembered a resource site, and its page on monsters: Monsters in Spelljammer has these lines:

Natural Spelljammer (Su):A natural spelljammer can attain spelljamming speed (100M miles perday) without the use of a spelljamming helm. This ability has the samerequirements for being far away from large objects as a ship with aspelljamming helm.
This ability provides no tactical rating (see Tactical Rating, below),unless otherwise stated in the creature's entry.
Only phlogiston or wildspace creatures (see Phlogiston Subtype andWildspace Subtype) can have this ability.

I don't know if such info is from 2e Spelljammer or homebrew though; and a quick search of the site does indicate that at least some monster listings therein have the trait.