The angle of the planes wings and tail are off. I think making the wings straighter, instead of so angled might help fix this.
Nice, but IMHO the grass should fade off in the distance, maybe a fade to blue would do the trick.
Those colors are soo much saturated. I dont like that its just an opinion. The shadows are equal to real ones for me it dont make it special but good work 
the birds make a u_u face. the objects thrown in kinda come across as compulsory, but beautiful nontheless
This is beautiful!