To dream of an airplane crashing represents plans, projects, or something you have just started that has now failed. Major setbacks, oversights, or disappointments. Something in your life that you were “getting off the ground” has become a disaster emotionally.
Example: A woman dreamed of seeing planes crash. In waking life she had survived Hurricane Katrina and was watching many of the plans she had for her life being completely destroyed.
Example 2: A woman had a recurring nightmare about being on an airplane that crashed. In waking life she was concerned about exciting business opportunities at work that she was involved with failing because she felt that they were too good to go on forever.