hi every one i have bloew  class ,i need a test class in order to deploy this as i create the test class but it cover only 74% i dont know which line is not coverd

Class

public with sharing class TestFlighRequestPage {
Test_Flight_Request__c fr;
public List<Opportunity> listOpp;
public String Id {get; set;}
private string result;

public TestFlighRequestPage(ApexPages.StandardController stdController)
{
fr = (Test_Flight_Request__c)stdController.getRecord();

if(fr.Id == null)
Id = ApexPages.currentPage().getParameters().get('opp');
else
Id = fr.Opportunity__c;

listOpp = [SELECT id ,Name, Departure_Date__c,Number_of_Passengers__c,Destination_Zone__c,Return_Date__c,
Origin_City__c,Destination_City__c,Flexibility_From__c,Flexibility_To__c
FROM Opportunity WHERE Id = :Id];

if(listOpp.size() >0)
{
if(fr.Opportunity__c == null)
{
fr.Opportunity__c = listOpp[0].Id;
}
if (fr.From__c == null)
{
fr.From__c = listOpp[0].Origin_City__c;
}

}
}




public void SendItineryEmail()
{
Test_Flight_Request__c FRdata = [SELECT Email_To__c, Subject__c,Email_Content__c
FROM Test_Flight_Request__c WHERE Id = :fr.Id];

Http h = new Http();
HttpRequest req = new HttpRequest();
req.setEndpoint(' ');
req.setMethod('GET');

HttpResponse res = h.send(req);
result = res.getBody();
String[] toaddress = new String[]{};
toaddress.add(FRdata.Subject__c);
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
mail.setToAddresses(toaddress);
mail.setSubject(FRdata.Subject__c);
string Emailbodydata = FRdata.Email_Content__c +'<br>'+ result;
mail.setHtmlBody(Emailbodydata);
Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });

}
}

TestClass

@isTest
private class TestFlighRequestPageTestCase {

static testMethod void myUnitTest() {
String message= '';
boolean flag= true;
String Id='';
double passengers = 0;

Contact con = new Contact();
con.FirstName = 'Anil';
con.LastName = 'Dutt';
con.Email = 'anil@swiftsetup.com';

Opportunity opp = new Opportunity();
opp.Name = 'Test Opp';
opp.StageName = 'Ticketing';
opp.p1_First_Name__c ='';
opp.p1_Last_Name__c ='';
opp.p1_Gender__c = '';
opp.p1_First_Name__c ='';
opp.p1_Last_Name__c ='';
opp.p1_Gender__c = '';
opp.DOB_Main_Passenger__c = System.now().date();
opp.Number_of_Passengers__c = 4;
opp.CloseDate = System.now().date();
opp.Departure_Date__c = System.now().date();
opp.Origin_City__c = 'DEL';
opp.Destination_City__c= 'MUI';
opp.Return_Date__c = System.now().date();
insert opp;

string oppID = opp.Id;

Test_Flight_Request__c fr = new Test_Flight_Request__c();
fr.Budget__c = '23';
fr.Publish_Fare__c = '35';
fr.Email_To__c ='anil@swiftsetup.com';
fr.Subject__c ='Test Mail';
fr.Email_Content__c ='Email Content';

List<Opportunity> listOpp = [SELECT id ,Name, Departure_Date__c,Number_of_Passengers__c,Destination_Zone__c,Return_Date__c,
Origin_City__c,Destination_City__c,Flexibility_From__c,Flexibility_To__c
FROM Opportunity WHERE Id = :opp.Id];

if(listOpp.size() > 0 )
{
if(fr.Opportunity__c == null)
{
fr.Opportunity__c = listOpp[0].Id;
}
if (fr.From__c == null)
{
fr.From__c = listOpp[0].Origin_City__c;
}

}

insert fr;
update fr;

Test_Flight_Request__c FRdata = [SELECT Email_To__c, Subject__c,Email_Content__c
FROM Test_Flight_Request__c WHERE Id = :fr.Id];

FRdata.Email_To__c = fr.Email_To__c;
FRdata.Subject__c = fr.Subject__c;
FRdata.Email_Content__c = fr.Email_Content__c;


try
{


ApexPages.StandardController sc = new ApexPages.StandardController(fr);
TestFlighRequestPage sc1 = new TestFlighRequestPage(sc);

sc1.SendItineryEmail();

Http h = new Http();
HttpRequest req = new HttpRequest();
req.setEndpoint(' ');
req.setMethod('GET');

HttpResponse res = h.send(req);
String result = res.getBody();
String[] toaddress = new String[]{};
toaddress.add(FRdata.Email_To__c);
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
mail.setToAddresses(toaddress);
mail.setSubject(FRdata.Subject__c);
string Emailbodydata = FRdata.Email_Content__c +'<br>'+ result;
mail.setHtmlBody(Emailbodydata);
Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });

}
catch(System.CalloutException e)
{
message = e.getMessage();
}
}
}