Just outside of Solitude...there is a dragon that will NOT land! Just keeps circling and circling and howling! No matter what I try he won't land.

Eh, you think you got it bad. I got a dead dragon called Dracolich that randomly pops up anywhere and everywhere.

There are actually Dragons that do just fly around and roar.
This is not a glitch in the game, I have a save that is gauranteed to have a Dragon fly over Whiterun and just circle a few times before disappearing.

Yup...I see these frequently when out in the wilderness. Successful troll dragon is successful, I guess.

Although if you have the Dragonrend Shout you can force them to aggro and land, I believe. At least I've done this with one troll dragon...not sure if that's how it's supposed to work with those (supposedly) non-hostile dragon encounters, though.

I used Dragonrend on one that was just circling over Hjaalmarch. I hit it and then watched it fly straight up into the air until it disappeared. Must've been Wuss the Cowardly Dragon.

Another member of the board said it's a glitch that occurs when a dragon spawns in an area that has no landing zones. In my experience, using Dragonrend on them sends them off into the distance, to the closest landing zone they can find (which is almost guaranteed to be too far away to make chase).

This seems to have become a more frequent problem with the recent patches. Imo, Bethesda really borked something, because I've been having problems in getting dragons to land in areas where it didn't use to be an issue, not to mention I've been seeing all kinds of wierd pathing issues, including dragons going into orbit after being hit with Dragonrend, and the infamous backwards-flying. This is with an unmodded game.

Not all dragons are out to kill. Some just want to spread their wings and fllllyyyyyyy! Dragon fly, sooooooooo hiiiiighh!

The bigger problem with this is it has the potential to break quests. I was trying to do the College quest line, but a dragon flying over head which refused to land caused all the NPCs to lose interest in the task at hand and heckle the dragon. So as usual, had to reload and fast travel to the Watch Tower near Whiterun to take it out before returning to the ruins.

You ain't kidding. Nothing like being unable to interact with NPC's because of a stupid dragon, which isn't acting like the passive scouting types yet is refusing to engage in combat with the PC.

This is not a bug in the game at all, this is a standard world encounter you can have spawn randomly in certain set locations as soon as you complete enough of the main quest for dragons to return. It's listed under the possible encounters as follows:

Dragon Flight

A dragon flies past you without attacking, unless you provoke it. [Main Quest: Dragon Rising must be completed]

I haven't finished the main quest, this is a bug.

That encounter only requires the quest "Dragon Rising" be completed, not the whole main quest. That's the second MQ mission (taking the message to the Jarl of Whiterun and then fighting your first named dragon at the Western Watchtower), and so a fairly easy quest to complete early on in a game.

Pages 409 - 412 of the Skyrim official game guide list random wilderness encounters. Encounters #8 and #10 are dragons that don't directly engage the player in combat unless the player attacks. These encounters can happen after the Main Quest: Dragon Rising is completed.

An unrelated phenomenon is when a flying dragon does attack but fails to land due to lack of a suitable landing spot--or does land on a roof or other inaccessible place. Players without good ranged attacks can influence this by walking or running to a location near a patch of flat ground. Be sure to remain near the perimeter if the landing spot is small so that the dragon has enough clear space for a landing.

My mistake.

The passive dragon thing is in the game to lend weight to the possibility that not all dragons are out to get you.
Experiencing passive dragons may influence your decisions later in the MQ, and if you are the kind of player who attacks first and asks questions later then you will miss this experience and its significance, which has been designed into the game.

Update: It landed today! I reloaded the same scenario multiple times and in 2 of 20 attempts, it landed. Bugged for sure.

Yea, dragons seem more prone to bugging out since patch 1.5. Encounter near Winterhold confirmed it for me - dragon was definitely hostile but circled endlessly without attacking. Moving one direction resulted in the dragon flying backwards. After several tries I finally got the dragon to attack normally. I don't recall having this kind of issue pre 1.5, after that disastrous patch that caused most dragons to fly backwards was fixed.

I've seen one fly straight up in the sky..and I mean straight up.

Not sure if this is the same as "endlessly flying around", but whenever I see non aggressive dragons fly past they don't tend to stay in my area long. Happened about an hour ago to me, I walked outside Whiterun and was walking down to "Your Highness" (shop on the outskirts of Whiterun added by a mod, not going deeper as Nexus lists it as advlt Only), and a dragon showed up, I insta-grabbed my bow thinking I knew what was going to happen, he circled overhead then almost immediately flew off towards Valtheim Keep/Tower. Maybe he had to go collect Amren's family sword?

Dragonrend always does the trick for me. If they won't land, force them to to land.

i don't think those dragons circling around is a glitch or a bug but actually scripted to create some atmosphere
and a sense of urgency and despair

Only when you try to force it to land it can become buggy

For my battlemage Derik I have a dragon the circles everytime he walks past the Bandit fort near Markarth, often flying right over his head. 159 hr's and no bugged/glitched quests for him. Just a random incounter.