Hello SecretCat!
I am a bit rusty in animation but I'll try to help you.
The main problem that I find here is that your character is losing mass.
More precisely on the frame the wings are closed.
Your frames are also spaced evenly and it reads better if you hold a frame or two on positions that take a lot of energy to change.
Ex: When the wings are fully extended and the dragon is pushing the air to go up.
To make it harder to push the air I added a frame after full extension, I also duplicated one frame and just moved it 1 px vertically to make the ups and downs stronger.
Here's how I would change it:
