Starring a haughty prince?

[SBC]

It's been a while since I read it, but Johanna Lindsey's Once a Princess might fit the bill.

[The Reading Raccoon]

The Cruel Prince

Everless

Glitter

Ash Princess

Falling Kingdoms

[Keith]

This is a tricky one because I can't think of a lot of books with "haughty princes" where the "haughty prince" isn't either a villain, a jerk-ish love interest for the actual protagonist, someone who needs to learn the error of his ways, or some combination of the three.

Some of Michael Moorcock's protagonists could perhaps count - Elric of Melniboné is a ruling emperor, but he spends most of his stories in voluntary or involuntary exile, so he's functionally similar to an "exile prince". He isn't always exactly haughty, but he generally seems to regard his abilities and position highly (not undeservedly, since he has literal gods on speed-dial). Corum: The Prince in the Scarlet Robe is another example who's actually a prince - again, he isn't always on top of things, but like Elric, he has a certain "most important person in the room" air which comes with being a member of an "elder race".

That reminds me of another princely protagonist who might qualify - Corwin from Nine Princes in Amber and its sequels.

[Rosa]

You don’t want the protagonist to grow and change? He’d be a flat character. Protagonists are by definition round characters.

[Rosa]

Gotcha. Princess Ben has this.

[Kirstin]

The Air Awakens series by Elise Kova. Part of the story is him growing as a character but it's by far not the whole of the story. On that note there are a lot of characters that grow throughout the series. There is also war, romance, sorcery and a whole lot more.