First create a class to represent your json data.

public class MyFlightDto
{
    public string err_code { get; set; }
    public string org { get; set; } 
    public string flight_date { get; set; }
    // Fill the missing properties for your data
}

Using Newtonsoft JSON serializer to Deserialize a json string to it's corresponding class object.

var jsonInput = "{ org:'myOrg',des:'hello'}"; 
MyFlightDto flight = Newtonsoft.Json.JsonConvert.DeserializeObject<MyFlightDto>(jsonInput);

Or Use JavaScriptSerializer to convert it to a class(not recommended as the newtonsoft json serializer seems to perform better).

string jsonInput="have your valid json input here"; //
JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
Customer objCustomer  = jsonSerializer.Deserialize<Customer >(jsonInput)

Assuming you want to convert it to a Customer classe's instance. Your class should looks similar to the JSON structure (Properties)