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Are pterodactyl bones mostly cancellous?

In my Anatomy course, we were discussing cortical bone and cancellous bone. My professor brought up that a lot of flying animals have a lot of cancellous bones in their body in order to lower the weight of their skeletons in order to be more efficient for flight. 

If this is the case, has it been found that flying dinosaurs have more cancellous bones than non-flying dinosaurs? Did this make flying dinosaurs weaker predators for bigger land prey?
gpt
1) pterodactyls are not dinosaurs. They are pterosaurs, an offshoot of archosauria, but not part of dinosauria. They are more like dinosaur cousins. They did live in the Mesozoic, but that does not make them a dinosaur.

2) Yes, pterosaur bones were exceptionally thin, hollow, and light. Practically paper-thin walls in some cases. This affects their preservation, and many pterosaur bones are found totally crushed.

3) Most (but not all) of the pterosaurs we know of were largely coastal, and probably fed on fish and other sealife. Probably didn't go after "bigger land prey" very much. For one, pteorsaurs were exceptionally light, with even the largest barely weighing more than the largest modern (flying) birds. Being too heavy makes flight all that much harder.

4) Flying dinosaurs--birds--do have thin-walled hollow bones, but this trait actually long predates what most people would definitively call birds, and is common to one extent or another in many coelosaurid theropods (and maybe even earlier).