To dream of an airline flight symbolises a project that is about to take off. If the flight is delayed, then is suggests that you are unprepared in undertaking the project at hand.

To dream that you miss your flight or a connection indicates that you are feeling helpless and trapped by some situation. You feel that you are being held back, either physically or mentally. Alternatively, the dream may also suggest that you are feeling disconnected in some aspect of your life – work, relationship or home life. 

To dream of flight signifies a new sense of freedom where you had previously felt restricted and limited.

*For an in depth analysis, see Common Dreams: Flying.