Gath Adams

Kayak is one of the top travel meta-search engines on the web, and they have a free API which allows you to get flight and hotel information.

To use the Kayak API, first get a developer key

Then you can read the full specifications to get the info. Or, just use the code below

This gets the flights given an Origin, Destination, Departure date and the number of travellers (note: Origin & Destination must be in the form of a 3 letter Airport code, eg: MEL = Melbourne, SYD = Sydney, LAX = Los Angeles).

You can also Download the full source code

    Private Function Flights(ByVal dtDepartDate As Date, _
        ByVal sOriginCode As String, _
        ByVal sDestinationCode As String, _
        ByVal iTravellers As Integer) As DataTable

        Dim sResult As String
        Dim oCookies As New CookieContainer
        Dim sURL As String
        Dim oDoc As New System.Xml.XmlDocument
        Dim sSID As String
        Dim sSearchID As String
        Dim bMorePending As Boolean = True
        Dim oTripList As System.Xml.XmlNodeList
        Dim oTrip As System.Xml.XmlNode
        Dim oFlights As DataTable
        Dim oFlight As DataRow
        Dim iFlightsFound As Integer
        Dim sDeveloperKey As String = "***Your Key Here****"

        'Full specs at: http://www.kayak.com/labs/api/search/spec.html

        'Get the SessionID
        sURL = "http://www.kayak.com/k/ident/apisession?version=1&token=" & sDeveloperKey
        sResult = sGetData(sURL, oCookies)
        oDoc.LoadXml(sResult)
        sSID = oDoc("ident")("sid").InnerText

        'Start the Flight Search & get the SearchID
        sURL = "http://www.kayak.com/s/apisearch?" & _
        "basicmode=true&oneway=y" & _
        "&origin=" & sOriginCode & _
        "&destination=" & sDestinationCode & _
        "&depart_date=" & Format(dtDepartDate, "MM/dd/yyyy") & _
        "&depart_time=a&" & _
        "return_date=" & _
        "&return_time=a" & _
        "&travelers=" & iTravellers & _
        "&cabin=b&action=doflights&apimode=1&_sid_=" & sSID
        sResult = sGetData(sURL, oCookies)
        oDoc.LoadXml(sResult)
        sSearchID = oDoc("search")("searchid").InnerText

        oFlights = dtFlightsTableInit()

        Do While bMorePending = True
            'Get the first lot of results
            sURL = "http://www.kayak.com/s/basic/flight?" & _
            "searchid=" & sSearchID & _
            "&c=10&apimode=1&_sid_=" & sSID
            sResult = sGetData(sURL, oCookies)
            oDoc.LoadXml(sResult)
            bMorePending = IIf(oDoc("searchresult")("morepending").InnerText = "true", True, False)
            If bMorePending = True Then
                'Wait for 5 seconds, then poll again
                System.Threading.Thread.Sleep(5 * 1000)
            End If
        Loop
        iFlightsFound = Val(oDoc("searchresult")("count").InnerText)

        'Build the final request, asking for the total number of flights found by Kayak.com
        sURL = "http://www.kayak.com/s/basic/flight?" & _
        "searchid=" & sSearchID & _
        "&c=" & iFlightsFound & _
        "&apimode=1&_sid_=" & sSID
        sResult = sGetData(sURL, oCookies)
        oDoc.LoadXml(sResult)

        oTripList = oDoc.SelectNodes("//trip")
        For Each oTrip In oTripList
            oFlight = oFlights.NewRow()
            oFlight("DepartDate") = oTrip("legs")("leg")("depart").InnerText
            oFlight("ArriveDate") = oTrip("legs")("leg")("arrive").InnerText
            oFlight("Airline") = oTrip("legs")("leg")("airline_display").InnerText
            oFlight("Price") = oTrip("price").InnerText
            oFlight("BookURL") = oTrip("price").Attributes("url").Value
            oFlights.Rows.Add(oFlight)
        Next

        Flights = oFlights
    End Function

    Public Function dtFlightsTableInit() As DataTable
        Dim dtFlights As New DataTable

        dtFlights.Columns.Add(New DataColumn("DepartDate", GetType(String)))
        dtFlights.Columns.Add(New DataColumn("ArriveDate", GetType(String)))
        dtFlights.Columns.Add(New DataColumn("Airline", GetType(String)))
        dtFlights.Columns.Add(New DataColumn("Price", GetType(String)))
        dtFlights.Columns.Add(New DataColumn("BookURL", GetType(String)))

        dtFlightsTableInit = dtFlights
    End Function

    Public Function sGetData(ByVal sURL As String, _
Optional ByRef oCookies As CookieContainer = Nothing) As String

        Dim Writer As StreamWriter = Nothing
        Dim WebRequestObject As HttpWebRequest
        Dim sr As StreamReader
        Dim WebResponseObject As HttpWebResponse
        Dim sbResultsBuilder As New StringBuilder
        Dim sBuffer(8192) As Char
        Dim iRetChars As Integer

        WebRequestObject = CType(WebRequest.Create(sURL), HttpWebRequest)
        WebRequestObject.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)"
        WebRequestObject.Method = "GET"
        WebRequestObject.Timeout = 55000
        WebRequestObject.ReadWriteTimeout = 55000
        WebRequestObject.AllowAutoRedirect = True

        If Not (oCookies Is Nothing) Then
            WebRequestObject.CookieContainer = oCookies
        End If

        WebResponseObject = CType(WebRequestObject.GetResponse(), HttpWebResponse)

        sr = New StreamReader(WebResponseObject.GetResponseStream)

        Do
            iRetChars = sr.Read(sBuffer, 0, sBuffer.Length)
            If iRetChars > 0 Then
                sbResultsBuilder.Append(sBuffer, 0, iRetChars)
            End If
        Loop While iRetChars > 0
        sGetData = sbResultsBuilder.ToString

    End Function

The Kayak API is pretty good, but does have some limitations, so I think is works best when you use it for stats rather than bookings. Anyone else know of some good travel APIs?