Wow great comments and feedback! I especially like the idea of a potential ability to shove people out of the way. I think that could definitely add an interesting choice to the player.
I think we needed some tutorial levels to explain better what the point of getting the coins and snacks was. Snacks increase your speed so you can clear the level faster. Coins/skymiles are tracked and if you are able to pick up enough (50 percent) then you can get an in-flight upgrade to better seats. The upgrade also lets you start the next run at higher stamina/speed (i.e. you felt refreshed after the flight). And if the timer runs out, you aren't eligible for the stamina upgrade.
But we weren't able to carve out more time to make this clearer in-game but it's definitely something we want to improve.
Thanks again for the comments!