Polymorph is nice,  but it only lasts for minutes per level. From a quick perusal, there's no upper size limit to what you can turn it into, though it can't be over 15 hit dice.  Depending on which kind of dragon you're turning him into,  that can go up to a Large size in some of the dragon types, and medium in others.<br/><br/>If you really want to be carried though,  just ask Sinthorn.  Can't do dragon form yet, but I can go up to a 18HD creature of a lot of other types, max huge.  For flying the party, I can turn into a huge winged dinosaur like reptile called the quetzocoatlus (No, not feathered serpant, alas....),  and carry 2128 lbs worth of stuff without being encumbered at fly speed 100 (poor)....and up to 6400 pounds at speed 66.   Plop an enlarge spell (Because I keep humanoid),  and the max load goes up to over 8 tons.  I can enlarge myself once a day for 15 minutes.<br/><br/>Alternatively,  there's a few ways of getting the huge dire bear to fly :).<br/>