Simple and you have some ideas that I haven't had before. Simple things, as using darker colors for text on the green button, instead of just using white. I usually use white, but using the darker one gave some distinct look and I like it. Nice work.
I love how each scene has little unexpected details.. the birds flapping to go up, the bump in the road, the plane perspective and waving, and the way the trees bend. It adds so much character to the animations. Great work!