@Background Pony #4D4C  
How do we know that that’s what he’ll actually grow up to be? The first time he grew to an adult size, he was influenced by Twilight’s magic, and the second time, he grew due to his greediness which in the show is explicitly stated to drastically speed up a dragon’s growth cycle.  
Also, something of note is that in Dragon Quest, many of the dragons, if not all of them, have wings, and the dragons he meets (winged, natch) are all older than him or it is implied to be that way, making them like “teenage” dragons. Since Spike is a “baby” dragon (think in relation to a dragon’s roughly 10,000-year lifespan), it would make sense that he hasn’t grown his wings yet, and that possibly in some growth spurt over the course of his life, his wings will grow.  
And on that day, everything will spontaneously combust all at once in a rainbowy explosion and then liquify into Tang.
 
Y’know, ’cause Tang.

@MadVillan  
I know I am right. We seen him grown twice.

@Background Pony #4D4C  
Keep trying.You’ll get it right one day.

Spike has no wings as an adult. And why do I keep seeing these ugly spawns of theirs?