<pnr>
    <outbound>
        <travellers>
            <person>
                <name></name>
                <address></address>
            </person>
            <person>
                <name></name>
                <address></address>
            </person>
        </travellers>
        <segments>
            <segment>
                <from></from>
                <to></to>
                <date></date>
                <flight-details>
                    <flight-id></flight-id>
                </flight-details>
            </segment>

            <segment>
                <from></from>
                <to></to>
                <date></date>
                <flight-details>
                    <flight-id></flight-id>
                </flight-details>
            </segment>
        </segments>
    </outbound>

    <inbound>
        ...
    </inbound>
</pnr>

class Pnr{
    Outbound outbound;
    Inbound inbound;
}

//Outbound
class Outbound{
    ...
}

//Inbound
class Inbound{
    ...
}