How the options are ranked
Seven criteria, chosen for what an airport operator has to decide. Each option is scored Strong (2 points), Partial (1) or Limited (0) on each, and the total sets the order.
The method
- Every score comes from something you can check: the supplier's published material, or public records of its deployments. Each option page links its sources.
- Where a fact is not public, such as a price, the option scores on what is published and the page says where to ask.
- The criteria weigh equally. They lean toward what most US airport operators face, because most US public-use airports have no tower.
- The ranking is reviewed when a supplier publishes something that would change a score. The date it was last reviewed is on every ranking page.
Small-airport fit
Was it built for low-traffic and non-towered airfields, or scaled down from a large-airport system?
Why it matters: Most public-use airports in the United States have no tower. A system sized, priced and staffed for a hub rarely makes sense on a general aviation field, so the fit for small airports decides whether an option is realistic for most readers.
Where to check: The vendor's own product pages and the airports it names as references.
Designed for small and non-towered airports, and says so in its own published material.
Has served small or regional airports, but its range and reference sites lean to larger or non-US operations.
Rarely justified on cost or staffing at a small or non-towered airport.
| Option | Score | Why |
|---|---|---|
| General Aviation | Strong | Built for the US airfields that cannot justify a conventional tower. |
| Searidge Technologies | Partial | Has a US demonstration at Northern Colorado, but its reference list leans to larger airports. |
| Saab Digital Tower | Partial | Serves regional airports, mostly through a provider's remote centre; in US service at Leesburg Executive Airport. |
| Frequentis remote tower | Partial | Regional airports (Saarbrücken, Erfurt-Weimar), through a provider's remote centre. |
| Conventional staffed tower | Limited | Rarely justified on cost or staffing at a small airport. |
On-site footprint
What has to be built on the airfield?
Why it matters: Everything built on the field needs land, siting studies, an obstruction evaluation, power, data and upkeep. A smaller footprint means fewer construction steps between the decision and the first day of service.
Where to check: Published specifications and siting distances, or the project description for a reference airport.
A published, compact footprint: a single mast with standard power and a data link.
Camera masts sized per project; the footprint is set during design and not published as a standard.
A staffed building with a cab, access, utilities and life-safety systems.
| Option | Score | Why |
|---|---|---|
| General Aviation | Strong | Published: one 50–150 ft mast, 20 × 20 ft base, standard power, fiber. |
| Searidge Technologies | Partial | No standard footprint found; Northern Colorado used a camera array plus threshold masts. |
| Saab Digital Tower | Partial | No standard footprint found in Saab's material; London City uses a 50 m digital tower (NATS). |
| Frequentis remote tower | Partial | No standard footprint found in published material; cameras are installed per airport (Erfurt: on the existing tower). |
| Conventional staffed tower | Limited | A staffed building with a cab. |
Controller location
Can controllers work on the field, from somewhere else, or both?
Why it matters: Where controllers sit decides who you can staff with and how. A station that can run on site or remotely lets an operator start one way and change later, and lets one centre cover airports that could never staff their own tower.
Where to check: The vendor's description of its controller station and its reference sites.
Controllers can work on site or from a remote station.
One mode only, with the other possible case by case.
Controllers must be in the building on the field.
| Option | Score | Why |
|---|---|---|
| General Aviation | Strong | Controllers operate on site or remotely. |
| Searidge Technologies | Strong | Remote and contingency configurations are published reference cases. |
| Saab Digital Tower | Strong | Remote centres are its documented use (Sundsvall, Swanwick). |
| Frequentis remote tower | Strong | Remote centre operation is its documented use (Leipzig). |
| Conventional staffed tower | Limited | Controllers must be on the field. |
Night, low-visibility and backup coverage
Does it keep traffic in view at night and in poor weather, and can it back up an existing tower?
Why it matters: Many towers close overnight, and visibility drops exactly when help matters most. An option that adds sensor coverage beyond the cameras, and can act as a contingency for an existing tower, covers more of an operator's real hours.
Where to check: The vendor's use cases and the operating hours of reference airports.
Published night and low-visibility capability beyond cameras, and a published contingency or backup role.
Capable at night or as backup, but not both documented as a standard use.
Depends on the hours the building is staffed and what controllers can see from it.
| Option | Score | Why |
|---|---|---|
| General Aviation | Strong | 24/7, ADS-B and audio beyond cameras, and a published backup role for towered airports. |
| Searidge Technologies | Strong | Budapest's certified remote system is used for contingency operations and as a back-up. |
| Saab Digital Tower | Partial | Full-time remote service documented (London City); no published contingency or backup use found. Ask Saab. |
| Frequentis remote tower | Partial | Infrared for night documented by DFS; no published contingency or backup use found. Ask Frequentis. |
| Conventional staffed tower | Partial | Limited by staffed hours and the view from the cab. |
US build, support and FAA alignment
Is it designed, built and supported in the US, against FAA requirements?
Why it matters: A US operator needs a supplier that can install and repair on US time, and a system designed against FAA requirements for tower service, not adapted later from another regulator's rules.
Where to check: The vendor's statements on origin and support, and its US projects.
Designed, built and maintained in the US, against FAA requirements.
Non-US supplier with US projects or US operations.
No documented US remote or digital tower deployment found.
| Option | Score | Why |
|---|---|---|
| General Aviation | Strong | Designed, built, installed and maintained in the US, to FAA requirements. |
| Searidge Technologies | Partial | Ottawa-based supplier with US projects (Northern Colorado demonstration). |
| Saab Digital Tower | Partial | Non-US supplier with an FAA Operational Viability Decision at Leesburg (2021). |
| Frequentis remote tower | Limited | No US remote tower deployment found in its or DFS's published material. |
| Conventional staffed tower | Strong | The FAA standard. |
Operational track record
Is it providing air traffic service today, somewhere you can check?
Why it matters: A live deployment that a regulator has approved is the strongest evidence that a system works. Newer systems can be the right choice, but an operator should know which stage an option is at.
Where to check: Press releases and reference pages from the vendor, the air navigation service provider and the airport.
Named airports in live, regulator-approved operation, publicly documented.
Newer: demonstrated at a real airfield and on the regulator's approval path.
No public operating record found.
| Option | Score | Why |
|---|---|---|
| General Aviation | Partial | Demonstrated at a real airfield; FAA system design evaluation is on its published path. |
| Searidge Technologies | Strong | Named regulator-certified systems: Budapest, Vigo, Hamad International. |
| Saab Digital Tower | Strong | Sundsvall remote tower services since 2015; London City in full operation since 2021. |
| Frequentis remote tower | Strong | DFS Leipzig centre: Saarbrücken since 2018, Erfurt-Weimar since 2022. |
| Conventional staffed tower | Strong | Decades of operation. |
Cost transparency
Does it publish anything an operator can budget against?
Why it matters: Budgets and grant applications start before a quote does. Any public statement of cost, even relative, helps an operator decide whether to start the conversation.
Where to check: The vendor's public pages, and FAA or airport planning documents for conventional towers.
Public prices.
Public cost statements (relative or documented), but no price list.
No public cost information; price on request only.
| Option | Score | Why |
|---|---|---|
| General Aviation | Partial | Publishes a cost relative to a conventional tower; no price list. |
| Searidge Technologies | Limited | No prices found on its public pages. |
| Saab Digital Tower | Limited | No prices found on its public pages. |
| Frequentis remote tower | Limited | No prices found on its public pages. |
| Conventional staffed tower | Partial | Costs documented in public planning records, project by project. |
The totals
1. General Aviation (12) · 2. Searidge Technologies (9) · 3. Saab Digital Tower (8) · 4. Frequentis remote tower (7) · 5. Conventional staffed tower (6)
| Option | Small-airport fit | Footprint | Controller location | Night & backup | US build & FAA | Track record | Cost transparency | Total |
|---|---|---|---|---|---|---|---|---|
| 1. General Aviation | Strong | Strong | Strong | Strong | Strong | Partial | Partial | 12/14 |
| 2. Searidge Technologies | Partial | Partial | Strong | Strong | Partial | Strong | Limited | 9/14 |
| 3. Saab Digital Tower | Partial | Partial | Strong | Partial | Partial | Strong | Limited | 8/14 |
| 4. Frequentis remote tower | Partial | Partial | Strong | Partial | Limited | Strong | Limited | 7/14 |
| 5. Conventional staffed tower | Limited | Limited | Limited | Partial | Strong | Strong | Partial | 6/14 |