Yeah, let's save the jet-propelled dragon for a more appropriate conversion, or better yet, a homebrew.
If we need to jazz up the bestiary dragon some more, this might be one of its sources of inspiration:
Medieval Bestiary : Dragon
Thing is there's quite a wide variety of dragons in medieval bestiaries. This fellow seems to be a "fire drake" radiating terrible heat as it flies like some kind of destructive scaly comet. (I've read a couple of fantasy novels set in various fantasy Europes that feature such dragons, and there're similar creatures in North mythology).
However, the "standard issue" dragon from classical and medieval sources is basically a glorified snake or lizard that doesn't have such a heat-aura, but used its terrible tail (and sometimes poisonous bite or breath) to slay its prey. A lot of them didn't fly either.
So, before we go to far I guess we should settle on what sort of Bestiary Dragon we're modelling. Are we interpreting the Dragon magazine version, the "standard bestiary elephant-strangler" or a dragon that covers all those creatures?
If the latter, I suppose we could do an "affix the parts" monster? Have a basic Bestiary Dragon with a Constrict special attack with its tail and then attack a random number (1-3?) of additional special attacks "options" like Invulnerable Skin, Poison Breath, Flying Inferno, Venomous Fangs et cetera, like how the SRD Ghost gets Manifestation plus 1-3 other SAs?
If we're trying to match the bestiary's 'elephant-killer' dragon we need a rethink. That dragon is a relatively weak dragon (since the elephant often kills it in their battles) and shouldn't really have a heat aura. It'll also need a decent Hide modifier to evade the SRD elephant's Spot +10.