PK 721 overlap

Fields:  { 'Dep.Port': 1, 'Arr.Port': 1, FlightNo: 1 }

Query: {
  "$or":[
  {"Carrier.Code":"PK","FlightNo":"267","EffDates.From":{"$lte":"2016-09-08T09:21:58.054Z"},"EffDates.To":{"$gte":"2016-09-08T09:21:58.054Z"}},
  {"Carrier.Code":"PK","FlightNo":"721","EffDates.From":{"$lte":"2016-09-08T09:21:58.054Z"},"EffDates.To":{"$gte":"2016-09-08T09:21:58.054Z"}},
  {"Carrier.Code":"PK","FlightNo":"789","EffDates.From":{"$lte":"2016-09-08T09:21:58.054Z"},"EffDates.To":{"$gte":"2016-09-08T09:21:58.054Z"}},
  {"Carrier.Code":"PK","FlightNo":"306","EffDates.From":{"$lte":"2016-09-08T09:21:58.054Z"},"EffDates.To":{"$gte":"2016-09-08T09:21:58.054Z"}},
  {"Carrier.Code":"PK","FlightNo":"797","EffDates.From":{"$lte":"2016-09-08T09:21:58.054Z"},"EffDates.To":{"$gte":"2016-09-08T09:21:58.054Z"}}
  ]}

[
  {
    "_id": "5784fe55255e8ca56451c423",
    "Dep": {
      "Port": {
        "Code": "DAC",
        "Name": "Hazrat Shahjalal International"
      }
    },
    "Arr": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "FlightNo": "267"
  },
  {
    "_id": "5784fe55255e8ca56451c424",
    "Dep": {
      "Port": {
        "Code": "DAC",
        "Name": "Hazrat Shahjalal International"
      }
    },
    "Arr": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "FlightNo": "267"
  },
  {
    "_id": "578500ab255e8ca5646d9f87",
    "Dep": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "JFK",
        "Name": "John F. Kennedy International Airport"
      }
    },
    "FlightNo": "721"
  },
  {
    "_id": "578500ac255e8ca5646da1c5",
    "Dep": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "FlightNo": "306"
  },
  {
    "_id": "578500ac255e8ca5646da1c6",
    "Dep": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "FlightNo": "306"
  },
  {
    "_id": "578500ac255e8ca5646da1c7",
    "Dep": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "FlightNo": "306"
  },
  {
    "_id": "578500ac255e8ca5646da1ec",
    "Dep": {
      "Port": {
        "Code": "KHI",
        "Name": "Jinnah International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "MAN",
        "Name": "Manchester Airport"
      }
    },
    "FlightNo": "721"
  },
  {
    "_id": "57850149255e8ca5647506c2",
    "Dep": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "JFK",
        "Name": "John F. Kennedy International Airport"
      }
    },
    "FlightNo": "721"
  },
  {
    "_id": "57850149255e8ca56475074e",
    "Dep": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "MAN",
        "Name": "Manchester Airport"
      }
    },
    "FlightNo": "721"
  },
  {
    "_id": "57850149255e8ca5647507c1",
    "Dep": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "YYZ",
        "Name": "Lester B. Pearson Intl Airport"
      }
    },
    "FlightNo": "789"
  },
  {
    "_id": "57850149255e8ca5647507c4",
    "Dep": {
      "Port": {
        "Code": "LHE",
        "Name": "Allama Iqbal International Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "YYZ",
        "Name": "Lester B. Pearson Intl Airport"
      }
    },
    "FlightNo": "797"
  },
  {
    "_id": "578501b5255e8ca56479dfe4",
    "Dep": {
      "Port": {
        "Code": "MAN",
        "Name": "Manchester Airport"
      }
    },
    "Arr": {
      "Port": {
        "Code": "JFK",
        "Name": "John F. Kennedy International Airport"
      }
    },
    "FlightNo": "721"
  }
]