@JakAttak - Thanks for all the pointers on the competition. I haven’t really had the chance to read all the posts. I also just got how this game relates to the theme. 
BTW, I just got a chance to actually try it out (vs. watching the video). Very cool!
It crashed on my iPad Mini
I changed my spherebox with earth to a free skybox with some clouds and a small intro zoom.
Thanks for the nice comments. Currently I’m most interested in learning a bit about making sweet graphics, so might not have time for any gameplay, just exploration of flying in the clouds. 
But the idea of gameplay would be to pick up fellow birds on their way south, avoiding obstacles and thunderclouds and being guided south by your special birdy sixth sense of direction…
@JakAttak did you get any error message? Have tried it on a iPad 2 and 3 here.
Made my last modification now, just hiding clouds that are in front of the camera and cleaing up some code. Made a Mesh class which is a bit smalltalk/jquery-inspired to write code like this:
Mesh("GSSkypx"):right(vec3(0,-1,0)):up(vec3(0,0,1)):rotate(45):quad(pos, width)
Which creates a rect with the specified right/up/rotation to handle position in 3D.
Well, it was fun to get motivated for getting some code done.