diff --git a/docs/user_stories.md b/docs/user_stories.md
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+++ b/docs/user_stories.md
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+# User story 1
+As an air traffic controller 
+So I can get passengers to a destination 
+I want to instruct a plane to land at an airport
+
+# Nouns
+air traffic controller, passengers, destination, plane, airport
+
+# Verbs
+get, instruct, land
+
+# Functional representation
+Objects:
+- plane
+- airport
+
+Messages:
+- land
+
+# Diagram
+Airport <--land--> Plane
+
+
+##################################
+# User story 2
+As an air traffic controller 
+So I can get passengers on the way to their destination 
+I want to instruct a plane to take off from an airport and confirm that it is no longer in the airport
+
+# Nouns
+air traffic controller, passengers, destination, plane, airport
+
+# Verbs
+get, instruct, take off, confirm
+
+# Functional representation
+Objects:
+- Airport
+- Plane
+
+Messages: 
+- take_off
+- left_airport?
+
+# Diagrams
+Airport <--take_off--> Plane
+
+Plane <--left_airport?--> true
+
+
+##################################
+# User story 3
+As an air traffic controller 
+To ensure safety 
+I want to prevent landing when the airport is full 
+
+# Nouns
+air traffic controller, safety, airport, full
+
+# Verbs
+ensure, prevent, landing
+
+# Functional representation
+Objects:
+- Airport
+- Plane
+
+Messages:
+- landing
+- full?
+
+# Diagrams
+Airport <--landing--> Plane
+
+Airport <--full?--> true/false
+
+
+##################################
+# User story 4
+As the system designer
+So that the software can be used for many different airports
+I would like a default airport capacity that can be overridden as appropriate
+
+# Functional representation
+Objects:
+- Airport
+
+Messages:
+- set_capacity
+
+Airport <--set_capacity--> num
+
+
+##################################
+# User story 5
+As an air traffic controller 
+To ensure safety 
+I want to prevent takeoff when weather is stormy 
+
+# Functional representation
+Objects:
+- Airport
+- Weather
+- Plane
+
+Messages:
+- prevent_take_off
+
+# Diagrams
+Airport <--take_off--> Plane
+Weather <--stormy?--> ture/false
+
+
+##################################
+# User story 6
+As an air traffic controller 
+To ensure safety 
+I want to prevent landing when weather is stormy 
+
+# Functional representation
+Objects:
+- Airport
+- Weather
+- Plane
+
+Messages:
+- prevent_landing
+
+# Diagrams
+Airport <--land--> Plane
+Weather <--stormy?--> true/false
+
+
+##################################
+
+# Edge cases
+- planes can only take off from airports they are in;
+# done
+- planes that are already flying cannot take off and/or be in an airport; 
+  (when plane lands left_airport? should be false)
+# done
+- planes that are landed cannot land again and must be in an airport
+# done
+
+##################################
\ No newline at end of file
diff --git a/lib/airport.rb b/lib/airport.rb
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--- /dev/null
+++ b/lib/airport.rb
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+require_relative 'plane'
+require_relative 'weather'
+
+class Airport
+  
+  DEFAULT_CAPACITY = 5
+
+  attr_reader :planes, :capacity
+
+  def initialize(capacity=DEFAULT_CAPACITY)
+    @planes = []
+    @capacity = capacity
+  end
+
+  def land(plane)
+    fail 'Airport full' if full?
+    fail 'Landing not allowed due to adverse weather' if stormy?
+    fail 'Plane already landed' if @planes.include?(plane)
+    plane.allowed_land
+    @planes << plane
+    plane
+  end
+
+  def take_off(plane)
+    fail 'Plane not in the airport' unless @planes.include?(plane)
+    fail 'Take-off not allowed due to adverse weather' if stormy?
+    plane.allowed_take_off
+    @planes.delete(plane)
+  end
+
+  private
+
+  def full?
+    @planes.length >= @capacity
+  end
+
+  def stormy?
+    weather = Weather.stormy?
+    weather
+  end
+          
+end
\ No newline at end of file
diff --git a/lib/plane.rb b/lib/plane.rb
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--- /dev/null
+++ b/lib/plane.rb
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+class Plane
+
+  def initialize
+    @left_airport = true
+  end
+
+  def allowed_take_off
+    @left_airport = true
+  end
+
+  def left_airport?
+    @left_airport
+  end
+
+  def allowed_land
+    @left_airport = false
+  end
+
+end
\ No newline at end of file
diff --git a/lib/weather.rb b/lib/weather.rb
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--- /dev/null
+++ b/lib/weather.rb
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+class Weather
+
+  WEATHER = [:sunny, :rainy, :stormy, :windy]
+
+  def self.stormy?
+    current_weather = WEATHER.sample
+    current_weather == :stormy
+  end
+
+end
\ No newline at end of file
diff --git a/spec/airport_spec.rb b/spec/airport_spec.rb
new file mode 100644
index 0000000000..4182e8ea59
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+++ b/spec/airport_spec.rb
@@ -0,0 +1,133 @@
+require './lib/airport'
+require './lib/weather'
+
+describe Airport do
+
+  # Capacity
+  describe '#capacity' do
+
+    it 'has a default value' do
+      expect(subject.capacity).to eq Airport::DEFAULT_CAPACITY
+    end
+
+    it 'can be set to a specific value' do
+      airport = Airport.new(10)
+      expect(airport.capacity).to eq 10
+    end
+
+  end
+
+  # Lands a plane
+  describe '#land' do
+
+    it 'airport responds to the method' do
+      expect(subject).to respond_to :land
+    end
+
+    it 'accepts one argument' do
+      expect(subject).to respond_to(:land).with(1).argument
+    end
+
+    it 'lands a plane' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = double (:plane)
+      allow(plane).to receive(:allowed_land)
+      expect(subject.land(plane)).to eq plane
+    end
+
+    it 'rasies an error when airport is full' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = double (:plane)
+      allow(plane).to receive(:allowed_land)
+      subject.capacity.times {subject.land(Plane.new)}
+      expect {subject.land(plane)}.to raise_error 'Airport full'
+    end
+
+    it 'raises an error when the weather is stormy' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(true)
+
+      plane = double (:plane)
+      allow(plane).to receive(:allowed_land)
+      expect{ subject.land(plane) }.to raise_error 'Landing not allowed due to adverse weather'
+    end
+
+    it 'raises an error when the plane has already landed' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = double (:plane)
+      allow(plane).to receive(:allowed_land)
+      subject.land(plane)
+      expect{ subject.land(plane) }.to raise_error 'Plane already landed'
+    end
+
+    it 'changes left_airport? to false' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = Plane.new
+      expect(subject.land(plane)).not_to be_left_airport
+    end
+
+  end
+
+  # Takes off a plane
+  describe '#take_off' do
+
+    it 'airport responds to the method' do
+      expect(subject).to respond_to :take_off
+    end
+
+    it 'accepts one argument' do
+      expect(subject).to respond_to(:take_off).with(1).argument
+    end
+
+    it 'raises an error when the weather is stormy' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = double (:plane)
+      allow(plane).to receive_messages(:allowed_land => nil, :allowed_take_off => nil)
+      subject.land(plane)
+
+      allow(weather).to receive(:stormy?).and_return(true)
+      expect{ subject.take_off(plane) }.to raise_error 'Take-off not allowed due to adverse weather'
+    end
+
+    it 'takes-off the plane when the weather is NOT stormy' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = double (:plane)
+      allow(plane).to receive_messages(:allowed_land => nil, :allowed_take_off => nil)
+      subject.land(plane)
+      expect(subject.take_off(plane)).to eq plane
+    end
+
+    it 'confirms the plane has left_airport?' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = Plane.new
+      subject.land(plane)
+      #expect(plane.left_airport?).to eq true
+      expect(subject.take_off(plane)).to be_left_airport
+    end
+
+    it 'raises an error when the plane is not in the airport' do
+      weather = class_double('Weather').as_stubbed_const
+      allow(weather).to receive(:stormy?).and_return(false)
+
+      plane = double (:plane)
+      allow(plane).to receive_messages(:allowed_land => nil, :allowed_take_off => nil)
+      expect{subject.take_off(plane)}.to raise_error 'Plane not in the airport'
+    end
+
+  end 
+
+end
\ No newline at end of file
diff --git a/spec/plane_spec.rb b/spec/plane_spec.rb
new file mode 100644
index 0000000000..ad79fc8153
--- /dev/null
+++ b/spec/plane_spec.rb
@@ -0,0 +1,27 @@
+require 'plane'
+
+describe Plane do
+
+  it 'responds to allowed_take_off method' do
+    expect(subject).to respond_to :allowed_take_off
+  end
+
+  it 'responds to _left_airport? method' do
+    expect(subject).to respond_to :left_airport?
+  end
+  
+  it 'after allowed_take_off returns true for left_airport?' do
+    subject.allowed_take_off
+    expect(subject).to be_left_airport
+  end
+
+  it 'responds to allowed_land method' do
+    expect(subject).to respond_to :allowed_land
+  end
+
+  it 'after allowed_land returns false for left_airport' do
+    subject.allowed_land
+    expect(subject).not_to be_left_airport
+  end
+
+end
\ No newline at end of file
diff --git a/spec/weather_spec.rb b/spec/weather_spec.rb
new file mode 100644
index 0000000000..ef8e2c2bf1
--- /dev/null
+++ b/spec/weather_spec.rb
@@ -0,0 +1,17 @@
+require 'weather'
+
+describe Weather do
+
+  it 'initializes with a weather constant' do
+    expect(Weather::WEATHER).to eq [:sunny, :rainy, :stormy, :windy]
+  end
+
+  it 'responds to stormy? method' do
+    expect(Weather).to respond_to :stormy?
+  end
+
+  xit 'responds with true or false to stormy?' do #could not make it work with a boolean
+    expect(Weather.stormy?).to be_in([true, false])
+  end
+
+end
\ No newline at end of file