The airplane, as a transportation symbol, signifies motivation and direction. Its association with flying can represent aspirations or your ability to 'soar.' You will usually dream of trying to catch a plane when you are making changes to your aspirations. This type of dream also occurs when you are attempting to let go of negative conditioning to feel more self assured. Missing a plane can symbolize a fear of failing. A plane that threatens to crash is another way of exploring your insecurities in light of the goals that you have set for yourself.
Airports and train stations are places of transition, and while the train depicts how you are breaking away from the tracks that were laid down for you as expectations of others, the airport represents ambition and is a place where you can 'fly' through expanded awareness and insight. Danger and the idea of crashing can reveal your insecurities about your ambitions. but does not necessarily mean that you will crash land. The dream is just allowing you to explore your insecurities so you might make necessary changes. It also allows you to strengthen your commitment to what you are trying to achieve.
Waking up within a dream to attempt the impossible, like flying can also be expressing a sense of power and accomplishment. It encourages the idea of how closely experience is tied to thought and beliefs. The flying dream generally occurs during periods of successful achievement or heightened inspiration. See Vehicles and Places of Transportation.