I have some reasons ehy I think it could be:  0:30 "I think I'm dying but I'm just being born" Pretty self explanatory  0:37 "Through the terminal we all shall go" We all have to die, it's terminal  The repeated use of "unusual" between 0:48 and 1:01 might be hinting towards death, as death would feel very unusual  1:06 "And I'm saying goodbye to the world I know" Again, death, leaving the world behind  1:15 "Through the terminal we all can grow" Rebirth perhaps?  1:20 "And it's time to let go" Letting go of the world, accepting your death  1:43 "...Imagining where all the planes are going" Reference to the possible existence of heaven?  1:56 "I'm on the next flight" Rebirth  2:02 "We'll fly through the night 
 till the
  day becomes bright" Being in a mother's womb until being born  2:05 "until the night returns" Until death again  2:31 "One day soon we'll all be together" We will all join each other after death
you are going to have a blast once you realize how far and wide you can use this analogy