The model, with the hood up.
A monthly, three-phase development model (model.py, reproducible) that a three-person red team took apart and rebuilt. Pick a scenario. Every number on this page is a projection, not a forecast.
Scenario explorer
Founder cash flow by year
Revenue, gain and guaranteed debt
What moves the answer
One change at a time from the go case (1.66x founder multiple, pre-tax). Hard cost dominates; deposit treatment and partner terms are next.
From 5.4x to honest
The first draft claimed 5.4x. It rested on several generous assumptions at once. Each bar adds one dose of realism, cumulatively, in the same monthly engine. The first bar approximates the draft's inputs, so it does not exactly reproduce 5.44x.
- Realistic entitlement (18 months to a lease, 9 to the presale gate)
- Buyer deposits held in escrow, not spent on construction
- Market capital stack: 65% LTC, 10% founder cash, 10% pref + 30% promote
- Bottom-up cost, dues, cap rate and dead-pursuit costs
Key assumptions
Kill gates
If any gate fails, the default is to stop, not to look for a reason to proceed.
| Gate | Threshold | Why |
|---|---|---|
| Counsel opinion | In writing before any pre-development spend | Deposit and hard-contract timing decide the capital stack |
| Closed-comp pricing | Blended ≥ $230/sf at the target airport | At $218/sf the plan returns ~1.0x |
| GMP | Hard ≤ $125/sf, all-in ≤ $170/sf, from two GC budgets | $135 hard returns 1.26x; $145 returns <1x |
| Sponsor | Approved ALP + NEPA, sponsor-funded taxilane and stubs, ≥ 40-yr term, ≤ $0.60/sf/yr | Timeline and cost |
| Demand | ≥ 40 type-qualified owners within 30 min; ≥ 16 refundable reservations in 60 days | ~2x coverage for 12+ hard presales |
| Rentals | No comparable box-hangar rentals at the field | Otherwise buy-vs-rent defeats the price |
| Lender | ≥ 65% LTC at ≤ 60% presales with a bonded GMP | Capital stack |
| Pre-development | Stop at $225k without a signed ground lease | Cap on dead money |
Run a single phase yourself.
The prototype's pro forma lets you move land rate, hard and soft cost, presales, prices, interest and retained units, with a live loan-unlock meter and sensitivity grid.