text: function Plane() {
  
  }
  
  Plane.prototype.land = function(airport){
    airport.clearForLanding(this);
  };
  
  Plane.prototype.takeOff = function(airport) {
    airport.clearForTakeOff(this);
  };
  
  // I want this object to invoke
  // the clearForLanding method
  // of the instance of the airport
  // class
  