There was a blog post a short while ago warning writers "Don't Fill Your Plot Holes with Dragons". (if someone finds the link, let me know and I'll add it). The writer made excellent points about realistic and unrealistic ways to deal with plot holes.
Just for fun, though, think of the advantages of using dragons.
Your character needs to be in a different location. Don't worry about climbing into a car or taking a train. Call a dragon.
Your main character is in danger with no way out. After cursing at yourself for writing yourself into a corner, remember your friendly dragon. Let him appear and scare the skin off of whatever is imperiling your character.
It's a cold night and your character is freezing. Hello, dragon! A bit of fire, if you please. Problem solved.
Your character has a deep secret, which you alluded to many times, but never actually figured out what it is. Solution? He has a pet dragon.
The dialogue drags. Talk about the dragon.
You discover your main character is, in fact, rather hum-drum. No one with a dragon is hum-drum.
Your main character needs a sidekick. How cool would a dragon sidekick be?
Your plot needs more conflict. The dragon can turn nasty.
Best of all?
Your main character is stuck in a deep hole. Oh, dragon??