# Airports Reference – Busiest Airports by Passenger Volume

> Airports Reference – Busiest Airports by Passenger Volume is a paid API for AI agents from airports-reference.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Returns a ranked list of the world's busiest large airports by annual passenger count, optionally filtered by country or continent.

## Facts

- Endpoint: GET https://airports-reference.x402tookit.com/big-hubs?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/airports-reference-busiest-airports-by-passenger-volume-ed36c0ea
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_n5rH-kiG_OcPnuFtnLldK

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability airports-reference-busiest-airports-by-passenger-volume-ed36c0ea
```

Example prompt: What are the top 15 busiest airports in Europe by annual passengers? Give me their IATA codes and passenger numbers.

## When to prefer this

Use this endpoint when you need to identify or rank major airports by passenger traffic volume globally or within a specific country or continent. Prefer this over a generic airport search when the use case is about hub size, traffic ranking, or identifying major aviation centers rather than finding a specific airport by code or location.

## Known failure modes

- Invalid continent code returns an error or empty result set
- Invalid ISO country code or unrecognized country name returns no results
- Limit value outside 1–50 range may be rejected or clamped
- Wikidata source may have outdated or missing passenger figures for some airports
- Degraded flag may be set if data source is partially unavailable

## How this service works

Busiest large airports ranked by annual passengers (latest Wikidata figure), optionally by country or continent.

## Output

A ranked array of airport objects each containing name, IATA/ICAO codes, rank, annual passenger count and year, latitude/longitude, elevation, country, region, municipality, and scheduled service flag. Also includes metadata such as data source attribution, an 'asOf' timestamp, applied filters, and optional summary/disclaimer fields.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "limit": {
       "type": "integer",
       "description": "Results 1 to 50 (default 15)"
      },
      "country": {
       "type": "string",
       "description": "Optional ISO country code or name"
      },
      "continent": {
       "type": "string",
       "description": "Optional continent code: AF AN AS EU NA OC SA"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "filter": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "country": {},
        "continent": {
         "type": [
          "null",
          "string"
         ]
        }
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "airports": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "lat": {
          "type": [
           "null",
           "number"
          ]
         },
         "lon": {
          "type": [
           "null",
           "number"
          ]
         },
         "iata": {
          "type": [
           "null",
           "string"
          ]
         },
         "icao": {
          "type": [
           "null",
           "string"
          ]
         },
         "name": {
          "type": [
           "null",
           "string"
          ]
         },
         "rank": {
          "type": [
           "null",
           "nu
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/airports-reference-busiest-airports-by-passenger-volume-ed36c0ea/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from airports-reference.x402tookit.com](https://www.zero.xyz/host/airports-reference.x402tookit.com/llms.txt)