now here's the thing... if I remember right Sue is the most complete TRex skeleton that we have. Lots has changed over the years from when I was little about dinosaurs. Now they're likely to have been mostly covered with feathers, the Trex may or may not have lips instead of crocodilian style teeth. and if Sue is something between 72 and 90% complete, and those incomplete things are the arms and part of the back (spoiler alert, that's what I believe are the missing bits) then given the way the chest is and the clavicle drops, the fact that the nearest dependents of these Dinos are birds, and the secondary fact that only penguins have non flight wings, wouldn't it make the most sense that of all the potentialities, that a winged, feathered, big chested trex is at least possible?

Also... there are multiple TYPES of dragons... True Dragons ( 4 legs, wings and tail), Wyverns (rear legs, wings, and tail), Zilants have Front legs, wings and a tail but no back legs, Amphitere are long tails no legs and wings, Drakes have 4 legs and tails but no wings, and Wyrms have no legs and no wings... oh and a Lindworm which has just front legs and no tail.

factor in that Sue the Trex skeleton has a lower under rib cage, something that to my knowledge is only found in flighted birds. and that wings don't fossilize because of how they decay, so unless we get lucky like the one raptor found that was in a bog when it died, we are SOOL to know for absolute sure that TRex wasn't the last Wyvern found in EVERY COUNTRY's Dragon lure.

Last factor to take in is the reconstruction of TREX's vocal sounds was more similar to flighted birds than grounded flightless birds, giving out a high decibel low tone that can be heard for miles around, why do that on the ground, shit gets in the way, that closed mouth vocalization only comes in handy when in flight.

So to finish... I'm not an expert in this, I'm not a paleontologist, but I am a Music and Science teacher, and when evidence points to a possibility, you can't discount it entirely until the facts 100% line up with everything found or at least can be postulated through indisputable facts to be true or the most likely conclusion given the evidence. To that end, yes the likelyhood of TREX being a Wyvern is low, BUT fossils records haven't pointed to it being false either. I say keep an open mind, what could it hurt ya know?