I stumbled across some relevant rules. The
broom of flying and
carpet of flying are vehicles rather than mounts. I'll discuss that in a bit. First, I'll respond to a couple of previous suggestions.
Have you considered bringing up the power of the other items so the broom isn't ahead of them? It seems like the issue is that the broom is basically a bit more powerful than it should be, and sure, you could solve that by making it weaker, but you could also give the other items other advantages that made them more viable. I think it's also worth noting that having an item grant you a movement type (and thus Dash) isn't purely beneficial - in some cases it would be more useful to a PC for the item to move independently and without using their Move at all.
This is not a bad idea. One issue I think I would have with implementation is that it would just make all of the flying items overpowered. Even with a very weak interpretation (or house rules) the
broom of flying is not only too strong compared to other flying items, it is very powerful for its rarity. It's a basic uncommon item that doesn't even require your attunement and automagically bypasses all flight and elevation challenges in the Exploration Pillar. That seems substantially more powerful for a party to have than for one of their warriors to have a +1 weapon. If I wanted to correct this by just raising the rarity on all of these items, then I couldn't use the random magic item tables in the DMG.
Sure, so my solution above was that you can sit on the Broom, but the only way you can give it instructions to go somewhere is by using an action and a command word.
In combat, this is akin to a really crappy maneuverability in previous editions. Dashing in-and-out isn't going to work, and even basic stuff (beyond "hover in place") is going to cost actions that will prevent you from attacking.
Out of combat, the action cost is much less important. And you are probably doing less tactical positioning as well. "go right above that tree" every few minutes isn't going to burn your action economy.
This is also not a bad idea. One reason I'd rather not go with that approach is because in previous editions you could ride it more like a mount, so this is more of a departure than I'd like. The other, probably more important, reason is that it would be terribly fiddly and probably end up in endless arguments at the table.
In any event, those are both reasonably good suggestions that someone might want to use, just not quite what I need.
Now onto the rules I stumbled across. As I said, the
broom of flying and
carpet of flying are vehicles rather than mounts. It's up to interpretation what that means in context, but here are the relevant bits.
Player's Handbook page 182
Characters in wagons, carriages, or other land vehicles choose a pace as normal. Characters in waterborne vessels are limited to the speed of the vessel (see chapter 5, "Equipment"), and they don't suffer penalties for a fast pace or gain benefits from a slow pace. Depending on the vessel and the sized of the crew, ships might be able to travel for up to 24 hours per day.
Certain special mounts, such as a pegasus or a griffon, or special vehicles, such as a carpet of flying, allow you to travel more swiftly. The Dungeon Master's Guide contains more information on special methods of travel.
Interestingly, while the
Basic Rules contains the same wording, D&D Beyond references a
broom of flying instead of a
carpet of flying. I'm not sure why it differs, but I'm assuming they both count as vehicles because of the similarity of their item descriptions, and how they differ from other movement-related items.
The Equipment chapter only lists some vehicle speeds in mph, so it's not useful. The DMG additional information is only slightly more useful.
Dungeon Master's Guide page 119
Flying by a spell or magic item works the same as travel on foot, as described in the Player's Handbook. A creature that serves as a flying mount must rest 1 hour for every 3 hours it flies, and it can't fly for more than 9 hours per day. Thus, characters mounted on griffons (which have a flying speed of 80 feet) can travel at 8 miles per hour, covering 72 miles over 9 hours with two 1-hour-long rests over the course of the day. Mounts that don't tire (such as a flying construct) aren't subject to this limitation).
Since the
broom and
carpet are magic items, one could use this as an argument that you can travel at different paces with them, and possibly by implication also Dash.
Alternatively, the same page also lists a single air vehicle (the airship) on an "Airborne and Waterborne Vehicles" chart, with a listed mph and other stats identical to water vehicles.
Since there are other magic items that allow flight but aren't treated as vehicles, I prefer to interpret the rules about "working the same as travel on foot" to refer to them, while the two items specifically called out as vehicles should follow the vehicles rules where possible. (This is just a matter of preference of interpretation--the rules are too sparse for there to be a clear winner.)
There aren't really any aerial vehicle rules in the DMG, or rather, they appear to simply be lumped in with the waterborne vehicle rules. Since that is the only precedent, I do feel the strongest interpretation of the PHB and DMG is to say that they follow what is written about water vehicles, meaning they have their own movement rate which doesn't really vary (and therefore shouldn't be Dashing).
We do have supplements that provide more rules on vehicles, and they can be instructive.
Baldur's Gate: Descent into Avernus has rules for land vehicles with magical engines. These vehicles move by means of the driver spending their Action to cause the vehicle to move. The driver can also use their Bonus Action to cause the vehicle to Dash. This movement appears to take place on the driver's turn. You can also pump Demon Ichor into the engine to get a temporary speed boost.
Ghosts of Saltmarsh provides rules more rules for waterborne vehicles. Waterborne vehicles roll their own initiative and have their own movement and Actions. Movement and various Action options require a certain number of crew to be present on the ship. These crew are spending their entire turns "too busy managing the ship to do anything else during combat", and do not appear to actually roll initiative. On the ship's turn, the captain decides where the ship moves and which Actions it takes. Officers apparently do roll their own initiative, as certain officers can use their Action to perform special actions. The Full Speed Ahead action increases the ship's movement by 1d6 x 5 feet until the end of its next turn, due to "exhorting the crew to work harder and drive the ship forward faster".
Eberron: Rising from the Last War provides information on elementally-powered vessels, including an airship. None of this information relates to tactical (round by round) level of movement, and instead provides only information about long range travel, which is given with a set mph value. As the rules in the book are the same for the airship and the waterborne galleon, this is additional evidence that airborne vehicles are intended to work more like waterborne vehicles than like land vehicles.
Waterdeep: Dungeon of the Mad Mage includes a spelljamming helm. It moves ships in a set mph speed (based on unexpended spell slots), rather than using Actions or Dashing and such.
Those are the only rules I'm aware of, though there may be more in some other adventure.
Let's talk a bit about Dashing, the Full Speed Ahead special ship's officer command, and ramifications.
A character's ability to Dash is limited. A character's movement rate outside of rounds is essentially based on moving their normal movement each round. A movement of 30 feet gives you a daily normal travel pace of about 26 feet per round, or a daily fast travel pace of about 33 feet per round. We also see this via the Chase rules in the DMG, where a character can only use their Action to Dash 3 + Constitution mod times before they need to start making Constitution checks to avoid taking (temporary) Exhaustion. Clearly, Dashing represents non-sustainable exertion rather than the movement speed a creature would have long term.
Just like Dashing, Full Speed Ahead relies on exertion from a crew and is not the vehicle's standard. While we have little in the way of rules for standard land vehicles (just magically powered infernal engines and lightning rail trains), it would seem reasonable that the creatures pulling wagons and such would be able to exert themselves for limited movement increase on a tactical scale, in a similar way to how characters can Dash. In like manner, as the PHB indicates, they can travel at fast, normal, and slow paces.
In the case of the
broom of flying and the
carpet of flying, it seems to me more consistent (and more importantly to me--more balanced with the other magic flight items) to disallow them to Dash, unless there is some sort of way to provide a magical boost to them. Those looking for a different experience might let them work like an infernal war machine, meaning the driver needs to use their Action to make them move, and could also use their Bonus action to make them Dash. In any event, the driver's own move isn't used to affect a vehicle.
So as far as Dashing goes, I'm fairly satisfied that I'm not going to allow these special vehicles to Dash, nor are they going to use the driver's movement (since no vehicle in the game does so).
The Stuff So Far
So it seems like there are 5e precedents that are either decent, or at least as good as any other interpretation, for implementing the following:
-
Broom of flying and
carpet of flying, as airborne vehicles, have their own turn.
-These items have a set movement and cannot Dash.
-The driver directs the item's movement on the item's turn, but does not otherwise effect it with their own move or actions.
So how do we determine when these items take their turn, given that they have no Dexterity score to roll initiative with? I think a good precedent can be borrowed from the Artificer's steel defender (and I think one or two other recent game elements). The steel defender acts on the same initiative as its owner, but takes its own turn immediately after its owners turn completes. The
broom and
carpet can function identically in combat, with the note that they can move on their turn, but can not take Actions.
This is nerfing the
broom quite a bit, but I'm not sure it's really enough to really firmly stick it into the "Exploration only" pillar like I want it. (Not that I would make a meta-rule that the item fails to function when initiative is rolled, just that I want combat usage to be thoroughly unappealing compared to the combat designed
winged boots or
wings of flying.)
The
broom of flying in particular could take some rules from the mounts section. In particular, rules about being dismounted. I think I'd like to say that you use half your movement to mount or dismount it, just like a mount,
and you use an Action to activate it. Since it takes its turn directly after yours, that means it can still move, so if you are just jumping on it to try to make an aerial getaway, that's still an option.
With all that, it
still feels too useful in combat. In addition to potentially getting knocked off if someone force moves your
broom or knocks you prone, I'm considering an additional house rule. If you or your
broom takes damage or if subjected to another situation that would require you to make a Constitution save to maintain concentration (whether or not you are actually concentrating and therefore whether or not you actually need to make such a save), you make the same DC 10 Dexterity save to see if you fall off. Based on the broom being a narrow and precarious platform to ride, I'm thinking of saying that if you aren't holding it with at least one hand you have Disadvantage on that save; and that moving on the broom without at least one hand free to hold it means that you also have to make this save or fall off.
So, the new
broom of flying. (The
carpet of flying follows the same vehicle based rules, but I wouldn't include the issues with needing to use half your movement to mount it, nor potentially getting knocked off. It's supposed to be a more powerful item, so I assume it cradles your feet and legs in such a way as to make it as stable as the floor.)
[EDIT: First draft version follows. An improved version based on feedback is in post #52]
Broom of Flying
Wondrous item, uncommon
This wondrous broom, which weighs 3 pounds, functions like a mundane broom until you stand astride it (following the rules for Mounting and Dismounting a creature in the
Player's Handbook) and speak its command word as an action. It then hovers beneath you and can be ridden in the air as an airborne vehicle. It has a flying speed of 50 feet. It can carry up to 400 pounds, but its flying speed becomes 30 feet while carrying over 200 pounds. The broom stops hovering when you land.
In combat, the broom shares your initiative count, but it takes its turn immediately after yours. It moves as you direct it, and takes no actions. If any other effect moves the broom against your will, or if you are not holding it with at least one hand when it moves at your direction, you must succeed on a DC 10 Dexterity saving throw or fall off the broom, landing prone on the ground and taking falling damage appropriate to the distance fallen (see chapter 8 in the
Player's Handbook). If you are knocked prone while riding the broom, or if you or the broom take damage or are subject to an environmental condition that might break concentration (whether or not you are concentrating on an effect), you must make the same saving throw. You have Disadvantage on this saving throw if you are not holding the broom with at least one hand.
You can send the broom to travel alone to a destination within 1 mile of you if you speak the command word as an action, name the location, and are familiar with that place. The broom comes back to you when you speak another command word as an action, provided that the broom is still within 1 mile of you.
Maybe that is enough.
