code: function( options, callback ) {
  
      debug( 'lookup' )
  
      var now = Date.now()
      var target = options.date.getTime()
  
      // NOTE: `.status()` is only available within a window of -7 to +3 days
      var timeMin = now - ( 8 * 24 ) * 60 * 60 * 1000
      var timeMax = now + ( 3 * 24 ) * 60 * 60 * 1000
  
      var method = target < timeMin || target > timeMax ?
        'schedule' : 'status'
  
      debug( 'lookup:time:target ', target )
      debug( 'lookup:time:window', timeMin, timeMax )
      debug( 'lookup:type', method )
  
      return this[ method ]( options, callback )
  
    }
docs: Look up a flight
  @param {Object} options
  @param {Date} options.date
  @param {String} options.airlineCode
  @param {String} options.flightNumber
  @param {?String} [options.airport] optional
  @param {?String} [options.direction='arr'] optional
  @param {?Array<String>} [options.extendedOptions] optional
  @param {Function} callback
  @return {Request}