If you want any elements that could fly in the sky, you may need to make Bird first, then you could combine Airplane, Angel, Eagle, Flying Fish, Owl, Parrot, Peacock, Penguin, Pigeon, Seagull, and Toucan. Making Bird is not complicated, after you created Life and Animal, things will be very easy. Check out the detailed walkthrough and try it yourself.
Fire + Earth = Lava
Lava + Earth = Volcano
Water + Water = Puddle
Water + Puddle = Pond
Water + Pond = Lake
Lake + Lake = Sea
Earth + Sea = Primordial Soup
Volcano + Primordial Soup = Life
Earth + Earth = Land
Land + Life = Animal
Animal + Air = Bird