diff --git a/.coveragerc b/.coveragerc
index 9cc8101cc7c..ff081214ec7 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -384,6 +384,7 @@ omit =
     homeassistant/components/sensor/onewire.py
     homeassistant/components/sensor/openevse.py
     homeassistant/components/sensor/openexchangerates.py
+    homeassistant/components/sensor/opensky.py
     homeassistant/components/sensor/openweathermap.py
     homeassistant/components/sensor/pi_hole.py
     homeassistant/components/sensor/plex.py
diff --git a/homeassistant/components/sensor/opensky.py b/homeassistant/components/sensor/opensky.py
new file mode 100644
index 00000000000..17e5f1f351c
--- /dev/null
+++ b/homeassistant/components/sensor/opensky.py
@@ -0,0 +1,141 @@
+"""
+Sensor for the Open Sky Network.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.opensky/
+"""
+import logging
+from datetime import timedelta
+
+import requests
+import voluptuous as vol
+
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.const import (
+    CONF_NAME, CONF_LATITUDE, CONF_LONGITUDE,
+    ATTR_ATTRIBUTION, ATTR_LATITUDE, ATTR_LONGITUDE,
+    LENGTH_KILOMETERS, LENGTH_METERS)
+from homeassistant.helpers.entity import Entity
+from homeassistant.util import distance as util_distance
+from homeassistant.util import location as util_location
+import homeassistant.helpers.config_validation as cv
+
+
+_LOGGER = logging.getLogger(__name__)
+
+SCAN_INTERVAL = timedelta(seconds=12)  # opensky public limit is 10 seconds
+DOMAIN = 'opensky'
+EVENT_OPENSKY_ENTRY = '{}_entry'.format(DOMAIN)
+EVENT_OPENSKY_EXIT = '{}_exit'.format(DOMAIN)
+CONF_RADIUS = 'radius'
+ATTR_SENSOR = 'sensor'
+ATTR_STATES = 'states'
+ATTR_ON_GROUND = 'on_ground'
+ATTR_CALLSIGN = 'callsign'
+OPENSKY_ATTRIBUTION = "Information provided by the OpenSky Network "\
+                      "(https://opensky-network.org)"
+OPENSKY_API_URL = 'https://opensky-network.org/api/states/all'
+OPENSKY_API_FIELDS = [
+    'icao24', ATTR_CALLSIGN, 'origin_country', 'time_position',
+    'time_velocity', ATTR_LONGITUDE, ATTR_LATITUDE, 'altitude',
+    ATTR_ON_GROUND, 'velocity', 'heading', 'vertical_rate', 'sensors']
+
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Required(CONF_RADIUS): vol.Coerce(float),
+    vol.Optional(CONF_NAME): cv.string,
+    vol.Inclusive(CONF_LATITUDE, 'coordinates'): cv.latitude,
+    vol.Inclusive(CONF_LONGITUDE, 'coordinates'): cv.longitude
+})
+
+
+# pylint: disable=unused-argument
+def setup_platform(hass, config, add_devices, discovery_info=None):
+    """Setup the Open Sky platform."""
+    latitude = config.get(CONF_LATITUDE, hass.config.latitude)
+    longitude = config.get(CONF_LONGITUDE, hass.config.longitude)
+    add_devices([OpenSkySensor(
+        hass, config.get(CONF_NAME, DOMAIN), latitude, longitude,
+        config.get(CONF_RADIUS))], True)
+
+
+class OpenSkySensor(Entity):
+    """Open Sky Network Sensor."""
+
+    def __init__(self, hass, name, latitude, longitude, radius):
+        """Initialize the sensor."""
+        self._session = requests.Session()
+        self._latitude = latitude
+        self._longitude = longitude
+        self._radius = util_distance.convert(
+            radius, LENGTH_KILOMETERS, LENGTH_METERS)
+        self._state = 0
+        self._hass = hass
+        self._name = name
+        self._previously_tracked = None
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state
+
+    def _handle_boundary(self, callsigns, event):
+        """Handle flights crossing region boundary."""
+        for callsign in callsigns:
+            data = {
+                ATTR_CALLSIGN: callsign,
+                ATTR_SENSOR: self._name
+            }
+            self._hass.bus.fire(event, data)
+
+    def update(self):
+        """Update device state."""
+        currently_tracked = set()
+        states = self._session.get(OPENSKY_API_URL).json().get(ATTR_STATES)
+        for state in states:
+            data = dict(zip(OPENSKY_API_FIELDS, state))
+            missing_location = (
+                data.get(ATTR_LONGITUDE) is None or
+                data.get(ATTR_LATITUDE) is None)
+            if missing_location:
+                continue
+            if data.get(ATTR_ON_GROUND):
+                continue
+            distance = util_location.distance(
+                self._latitude, self._longitude,
+                data.get(ATTR_LATITUDE), data.get(ATTR_LONGITUDE))
+            if distance is None or distance > self._radius:
+                continue
+            callsign = data[ATTR_CALLSIGN].strip()
+            if callsign == '':
+                continue
+            currently_tracked.add(callsign)
+        if self._previously_tracked is not None:
+            entries = currently_tracked - self._previously_tracked
+            exits = self._previously_tracked - currently_tracked
+            self._handle_boundary(entries, EVENT_OPENSKY_ENTRY)
+            self._handle_boundary(exits, EVENT_OPENSKY_EXIT)
+        self._state = len(currently_tracked)
+        self._previously_tracked = currently_tracked
+
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return {
+            ATTR_ATTRIBUTION: OPENSKY_ATTRIBUTION
+        }
+
+    @property
+    def unit_of_measurement(self):
+        """Unit of measurement."""
+        return 'flights'
+
+    @property
+    def icon(self):
+        """Icon."""
+        return 'mdi:airplane'