What causes air pockets in crepes?
To me it looks like the crepe batter is sticking unevenly to the cooking surface. As the crepe cooks, steam is released from the bottom. In some areas the crepe sticks to the pan and prevents the steam from escaping; it gathers into bubbles. (As the crepe continues to cook, the surface dehydrates and proteins contract, releasing the crepe, so this doesn't necessarily lead to sticking when you attempt to flip the crepe.)
It's hard to tell from your photos, but I guess you're cooking on a cast iron skillet? Before you start cooking crepes, oil it and bring it to smoking temperature, then wipe with a dry paper towel and allow to cool to cooking temperature. Re-oil immediately before you start cooking the crepe. If there's any significant rough carbon deposits, try reseasoning.
Finally, if you like lacy crepes, try whisking the batter just before pouring it. The small bubbles are what cause the laciness, and they'll also act to release the pressure that would otherwise develop into large bubbles.