Method
Everything on the Future state pages follows from the rules on this page and the public data named here. Nothing is estimated by hand, and no document or data from any government or company that is not public was used.
1. Airport classes
Each assessed airport gets the first class that fits.
- Remote or digital, already listed (R). Matches an operational, trial or planned site in the tower dataset by ICAO code.
- Staffed tower today (T). Has a tower frequency in OurAirports, or the tower flag in the FAA forecast for US airports. This is a proxy: it does not prove the tower is staffed all day, and OurAirports frequency lists are incomplete in some countries.
- No tower, scheduled passenger service (S). The OurAirports scheduled-service flag.
- No tower, traffic above threshold (G). A movements or passenger figure at or above the tier 2 level.
- No tower, infrastructure proxy (P). No traffic figure exists in the loaded tables, but the runway and nearby population suggest a busy airfield.
- No tower, isolated (I). Far from every other reference airport. This is a distance proxy for remote, medical or island access. No road, medical or ferry data was used.
- Below threshold (N). Assessed but not a candidate. Counted, not mapped.
2. Suggested service tiers
Full remote tower service
Air traffic control from a remote centre for extended hours or around the clock.
Part-time remote tower
Remote air traffic control in busy periods, advisory service the rest of the day.
Remote advisory (AFIS-like)
Remote flight information and traffic advisories. Not air traffic control.
Surface awareness only
Cameras and surveillance feeds that give an operator or pilots a picture. No separation service.
Large hub: augment or keep as is
Too large for the simple remote model. Digital augmentation or contingency use only.
3. Every threshold
| Rule | Value | Input |
|---|---|---|
| Airport is assessed | Type small, medium or large; not closed; not military by name; and scheduled service, or a tower, or a runway of 800 m or more. United States: only airports in the FAA forecast, or with scheduled service or a tower. | OurAirports; FAA Terminal Area Forecast |
| Tier 1 (staffed tower today) | 20,000 or more movements a year, or 250,000 or more passengers | National traffic tables |
| Tier 2 (staffed tower today) | 4,000 or more movements, or 10,000 or more passengers | |
| Tier 3 (staffed tower today) | Traffic known and below the tier 2 level | |
| Hub, left alone | 150,000 or more movements, or 5,000,000 or more passengers | |
| Tier 1 (no tower, scheduled service) | 100,000 or more passengers, or 30,000 or more movements | |
| Tier 2 (no tower, scheduled service) | 10,000 or more passengers, or 8,000 or more movements | |
| Tier 3 (no tower, scheduled service) | Below the tier 2 level | |
| Tier 1 / Tier 2 (no tower, no scheduled service) | 30,000 or more movements is tier 1; 8,000 or more movements is tier 2 | Needs a movements figure (United States forecast, UK, Australia, part of Canada) |
| Tier 3 by infrastructure proxy | No tower, no traffic figure, paved runway of 1,200 m or more, and 25,000 or more people within 25 km | OurAirports; GeoNames |
| Tier 4, isolated | No tower, runway of 600 m or more, and no other reference airport within 100 km (reference = scheduled service, a tower, or a paved runway of 1,200 m or more) | OurAirports |
| Unknown traffic, staffed tower | Large airport class is a hub; medium is tier 1; small is tier 2 | Size class from OurAirports |
| Unknown traffic, scheduled service, no tower | Medium or large class is tier 2; small is tier 3 | |
| Hypothetical centre | Up to 20 workload units (tier 1 = 1, tier 2 = 0.5, tier 3 = 0.25); airports within 500 km and 20 degrees of longitude of the centre; same country | Greedy placement, existing facilities first |
| People gap | People in cities of 15,000 or more within 50 km of an airport, each city counted once | GeoNames cities15000 |
4. Where hypothetical centres go
Within each country, the airports in tiers 1 to 3 (not hubs, not already remote) are grouped. Candidate sites are airports with a staffed tower today and a medium or large size class, plus operating, trial or planned remote tower centres from this site's dataset. A greedy search picks the site that can take the most workload within 500 km, prefers existing remote tower centres and then existing staffed facilities, and repeats until every airport is placed. If no existing site is in range, the airport itself becomes a "new site", which is penalised so it is used last. Centres never cross a national border. Workload units are an illustration of shared capacity, not a staffing analysis.
5. Data inputs
- Airports, runways, frequencies: OurAirports open data (public domain), pulled 11 October 2026.
- Populations: GeoNames cities of 15,000 or more (CC BY 4.0); national population from the World Bank (SP.POP.TOTL, 2024).
- Existing remote and digital towers: the dataset on this site, every row with its own sources.
- Traffic: per country, below. Where a table is missing, tiers fall back on infrastructure, and the country page says so.
6. What this is not
- It is not a recommendation to any authority, airport or air navigation service provider.
- It is not a business case. There are no costs, benefits or demand forecasts here.
- It does not know local terrain, weather, airspace, labour agreements, safety history or politics.
- Tiers can be wrong for any single airport. Use the airport list as a starting question, not an answer.
7. Traffic sources by country
Data downloads: summary.json · airports.csv (every candidate airport in the country-page countries, with class, tier and reason) · world_points.json · world_centers.json. Free to reuse with attribution to digitaltowers.org.