I'm writing a story where there's a civil war fought by people with weapons and technology based on 50s experimentals, kind of like a subtle "What-if" aesthetic.
How can I manipulate what tactical situations they have to face (by means of things like geography, certain limitations on their technological capabilities, etc) where armed jet pack pilots are the superior choice?
Enemies also have jetpacks!
Because the only thing cooler than soldiers with jetpacks fighting enemies through a Jetsonesque city of the future is when their enemies have jetpacks too! They dodge around the buildings, ducking in and out and around them. Flying soldiers shoot watertowers to drench their enemies. Enemies knock over billboards onto enemies who shoot a hole as it comes down so they dont get hit. Jetpacks spinning out of control. Apparent returning jetpack solider is actually a mannikin in enemy uniform flying captured jetpack and carrying bomb! Flock of jumpjet soldiers flying up out of the subway!
Jumpjet vs jumpjet 3d urban warfare. Oh yes.
Your jetpack troops are combat engineers (let's face it, jetpacks are temperamental things and it takes technical know-how to keep them working in the field) and their duties are the traditional duties of engineers: establish routes that other troops will use to follow them, sabotage enemy routes and fortifications, and clear out any obstacles that would stop the rest of the army.
For pioneering work, jetpack troops are ideal for establishing a beachhead. Whether it's literally storming a beach and taking gun emplacements on the sea cliff, jetting over a river to surprise dug-in enemies, or bypassing an enemy-held bridge, they are invaluable for securing an area long enough for the rest of the army to catch up. Even if you're not under fire, being able to jump over rivers and up cliffs is a huge leg up when building bridges or setting ropes for others to follow.
For sabotage they're even more valuable, able to bypass all kinds of passive defenses (walls, barbed wire, even mines) that enemies might leave around their fortifications. Their unmatched mobility lets them make quick, surgical cuts against targets like rail lines, artillery emplacements, or communication towers that other troops can't touch.
Urban combat in extremely build environments. A rocket launcher and a team of specialist entering through a window or roof of skyscraper. Allowing bypassing the most obviously defended areas of underground and surface level.
These could be tactical pinpoint strikes against high value targets or pincer moves combined with more traditional ground based action. Building a bridgehead for ziplines and like for exit and entry. Or maybe retrieving high value objects from such location.
Main issue with jetpacks is limited travel time and distance. As such entering and possibly exiting a building would be a use case that could be somewhat realistically possible.
I am assuming these are the classic backpack-worn jetpacks.
A Jetpack gives an immense mobility to the user. Even in flat terrain with a low amount of houses the ability to reach anything above ground floor quickly without passing the ground floor is immensely valuable. The more urbanized and the rougher the terrain the more powerful these jetpackers become.
first of all just the fact that you can move pretty fast across terrain without it costing you much stamina is a massive boon and justifies the jetpack even if it didnt fly. Everything else is just gravy.
normally assaulting a beach can only happen at specific terrain, while jetpack users can quickly scale any type of beach. Even as "simple" skirmishes behind the rear line they would be immensely valuable. The fact that they arent relying on an outside source (say a helicopter) means they remain effective and low profile for much longer.
many terrain can severely limit movement. Ukraine's rain season is a good example where everything gets so muddy only roads are really available. Another example is the Winter War where the simple act of having soldiers capable of using ski's gave such an immense advantage the Finns managed to (barely) hold back the superior Russian numbers and vehicles. Jetpacks massively increase the mobility across any terrain, from mountains to deep snow to swamps.
rivers are a natural obstacle that are immensely hard to overcome. Boats and pontoon bridges take time to get people across and they are extremely vulnerable (again, the Russian's tried to cross a river in Ukraine and lost almost the entire group). Being able to quickly and relatively safely cross the river and skirmish would reduce the advantage of a river (but not eliminate it). It also means its easier to set up a perimiter in order to get non-jetpack troops across using regular boats and pontoonbridges.
parachuting? Thats pretty dangerous! Not a couple of years before during WWII many parachutists died due to getting stuck on their descend or hitting stuff they shouldnt hit like power lines. With jetpacks you have an immense control over where you land and how, letting large groups land in a smaller area if you need it.
someone else already mentioned it but combat engineering. It doesnt matter if its simply laying down a telephone line, deploying a bomb meant to clear barbed wire or bringing a flamethrower/explosives up to that Pillbox from an angle pillboxes arent normally designed to shoot at.
Rapid treatment by Combat Medics. As you can see in this video, a person with a jetpack can reach a remote casualty very quickly. This is very important for dealing with traumatic injury quickly as death rates can go up very quickly when treatment is delayed.
Paratroopers are great for inserting infantry in hard-to-reach places, but it's a one-way trip. They either win the battle, or they're stuck with no escape. A jetpack would give your infantry an escape mechanism. When things get rough, send in an empty troop carrier plane and your surviving paratroopers can jet back up and escape. They'd be quite vulnerable during this trip, but it's a lot less dangerous than being trapped in a no-win situation.
This doesn't just apply to paratroopers, either. Any small band of stranded personnel can be rescued by air-dropping a crate of jetpacks and having them jet-jump up to the evacuation craft. The evacuation craft can remain at altitude and not risk coming under direct fire by landing. Many small, independently-moving targets are harder to take out than a single evac chopper sitting on the ground. You could even do something similar for a spy who has completed their mission: copy the enemy's battle plans, grab the jetpack you stashed away, and get out before you can get caught. You'd completely blow your cover, but it might be worth it if it means better odds of making it home alive.
Since you're talking about a retro-future aesthetic: jetpack troops would be very useful in a world with airships/dirigibles. Technicians can fly up to inspect an airship or do simple repairs without forcing the ship to land. Boarding parties and sabotage crews could use jetpacks to assault enemy craft or capture it without shooting it down.
Whenever human carrieable ranged weapons are outclassed by armor (but melee weapons aren't or to a lesser degree)
I got this idea from Rimworld actually. Whenever you have melee weapons with a reasonable (even if situational) big enough advantage over ranged ones (aka not our current reality), jetpacks make sense. When plasmaswords can cut trough power-armor that any carrieable ranged weapon can't touch, a melee jetpack trooper is necessary, even if only to charge at the opponents entrenched big guns that could actually hurt your own power-armor troops.
Its basically return of the cavalry, unaffected by mines and machine guns. They would penetrate, and then prepare- roll up the rear area of stagnant and stationary fronts. That is until someone deploy cram like sentry-turrets preventing close-air support. But even then, if the jet pack is light enough, it allows for "hunting" jump attacks, that are extremely counter-intuitive to human danger expectations and defense behavior. You do not storm buildings from bottom up- you enter like a defender from the roof, or windows simultaneously.
You can hop over small islands of nomansland with wire into the parallel trench, if that trench ahead of you is blocked. You can carry larger loads , as the jet pack can support you.
You can - with good enough sensors and automatics, out-fly precision artillery and fpv drones, turning a hunt for you into a game of flak on the ground. All terrain that is perceived as "non-climbable" like cliffs, swamps or dangerous ruins, even small lakes or bays of the ocean, become approach vectors. In the best case, you simply walk into unguarded rear are, hoping from ammunition depot to ammunition depot, wreaking havoc with time delayed bombs and firecrackers, while long gone, short rest, then back into the air for more havoc.
When a fierce flood invaded Prague, I and my employees from my security company were saving people using a security towboats. Some of us even used our airbeds.
Imagine such scenario with JETPACK SECURITY WORKERS / SOLDIERS!:) They are much faster, can get even inside of buildings, can start from any solid surface and land there...
If you want a war scenario, imagine a city under missile attacks so anything bigger in the air get shot, all dams and water towers in the city are nearly destroyed - so there is a flood.
