There are a few reasons your American pancakes may not be fluffy, such as overmixing the batter. If this occurs, you will find the pancakes are chewy, not fluffy. Ensure you are just mixing the batter until everything is incorporated, and it should fix your pancakes.   Additionally, you may have forgotten to include baking powder or baking soda, which help create that fluffy consistency. Double check you've included every ingredient for the best outcome.