Building the airline sim I always wished existed
Hi r/tycoon - longtime reader here. I've been working on a singleplayer airline management sim called Skyline for about the past year, and I think it's finally at the point where it's worth showing publicly.
Part of why this project exists is because I bounced off AirlineSim a few years ago. I loved the depth, but I couldn't sustain the daily login economy and always online structure.
There's a gap between "deep airline simulation" and "playable single-player strategy game," and Skyline is basically my attempt to live in that space.
A few things already working in the current build:
The simulation engine is deterministic and pure-functional. Same seed means byteidentical outcomes. You can replay saves and test alternative decisions while keeping the rest of the world fixed.
Demand is modeled per origin/destination pair using a gravity model calibrated against US DOT T-100 data and Eurostat avia_par filings. Aircraft performance uses BADA methodology, which is the same framework used in real route planning and fuel-burn modeling.
The world simulation includes historical macro conditions:
- fuel prices
- FX rates
- GDP
- interest rates
- historical events
So if you start in 2007 and play through 2008, demand actually collapses. Oil shocks affect airline economics. COVID hits in 2020.
Fleet acquisition is probably the system I'm happiest with so far.
Aircraft production slots are real and tied to delivery dates. You can option aircraft, firm them up later, lock engine selections at production milestones, and configure cabins closer to delivery. Financing matters too. Right now there are six financing paths:
- cash
- finance lease
- operating lease
- sale-leaseback
- EETC
- export credit
Each affects your balance sheet and cash flow differently.
There's also:
- a used aircraft market
- condition gradings
- multiple lessor archetypes
- AI airlines competing for slots and financing
The founding flow is already playable too. You choose:
- jurisdiction
- funding structure
- network strategy
- airline archetype
Those early choices propagate forward through the simulation. The goal is for decisions made on day one to still matter decades later.
The AI airlines run under the same rules as the player. They expand, retreat from weak markets, negotiate aircraft, overextend, and sometimes go bankrupt. New entrants appear if market conditions make them viable.
A few things that are NOT finished yet:
Connecting passenger flows are not implemented yet. The next major work block is the passenger route-choice model:
- nested logit
- frequency preference
- connection penalties
- hub dominance effects
That's the layer that really differentiates hub and spoke airlines from point to point carriers.
Cabin classes exist structurally, but revenue differentiation is still WIP.
Seasonality currently uses a handtuned first pass model. Full calibration against historical residuals is deferred for now because I'd rather ship something honest and iterate on it.
No cargo yet either. Belly cargo on widebodies is something I want in. Dedicated cargo ops are probably further out.
And no, I still don't have a great answer for late-game micromanagement scaling. That's one of the harder design problems left.
A few things I've intentionally decided not to do:
- no multiplayer
- no progression-locked eras
- no airport builder
- no real airline branding in the base game
You pick any era from the 1990s onward and just start.
If anyone wants to follow development:
Devlog: https://skylinesim.app/blog/why-skyline
Discord: https://discord.gg/HsqucsgsGd
I'm probably 14-18 months away from a closed alpha. That's my honest estimate, not a marketing estimate.
Happy to answer questions about any part of it:
- simulation architecture
- calibration
- AI airlines
- passenger behavior modeling
- airline economics
- scheduling logic
- whatever else people are curious about
And genuinely open to criticism or pushback too. That's mostly why I'm posting this.