Well, the raven is from the kingdom Animalia, whereas the maple tree is from the kingdom Plantae so they're actually very different.
Ravens can in fact fly as you have stated before and are in the Corvus genus.
Maple trees are in the genus Acer and cannot fly.
Maple trees have leaves that capture sunlight for energy.
They also have roots that get nutrition from the soil and water from the ground.
Ravens eat things like nuts, fruits, insects and whatnot for energy.
There are so many differences to name between the two, I can't list them all