Super nice - you have a solid gameplay loop here!
You even cannot stop flying right? So there is ALWAYS something to do for the player and it technically never gets boring right - very very nice and full of potential!
Presentation works fine and it is very satisfying to fly - I personally would like to have more control like that I can boost myself and recharge by collecting the rings. Or tighter turning haha.
The theme also works fine however I never felt generous but more like doing my job being the cargo plane between the three locations. Also I feel like a week of playtime is a bit long - at a point I was missing a concrete goal or like a bigger in-between reward (you can dismiss this since it is a game jam and I am starting to daydream while writing ...)
Great job and really really nice game there fellas! Do you want to continue working on the project after the jam?