code: function( options, callback ) {
  
      debug( 'route', options )
  
      var self = this
  
      var year = options.date.getFullYear()
      var month = options.date.getMonth() + 1
      var day = options.date.getDate()
      var direction = /^dep/i.test( options.direction ) ?
        'dep' : 'arr'
  
      var url = 'flightstatus/rest/v2/json/route/status/' + options.departureAirport + '/' + options.arrivalAirport +
        '/' + direction + '/' + year + '/' + month + '/' + day
  
      var extensions = [
        'useInlinedReferences'
      ]
  
      if( Array.isArray( options.extendedOptions ) ) {
        extensions = extensions.concat( options.extendedOptions )
      }
  
      return this._clientRequest({
        url: url,
        extendedOptions: extensions,
        qs: {
          maxFlights: options.maxFlights,
          codeType: options.codeType,
          numHours: options.numHours,
          utc: options.utc,
          hourOfDay: options.hourOfDay,
        }
      }, function( error, data ) {
        callback.call( self, error, data )
      })
  
    }
docs: Get routes between two airports
  @param {Object} options
  @param {Date} options.date
  @param {String} options.departureAirport
  @param {String} options.arrivalAirport
  @param {String} options.codeType
  @param {Number} options.maxFlights
  @param {Number} options.numHours
  @param {Number} options.hourOfDay
  @param {Boolean} options.utc
  @param {Array<String>} [options.extendedOptions]
  @param {Function} callback
  @return {Request}