Even i had the same issue. Later i came to know that all the api (which you get during singn up process) are blocked by default. You have to write a mail to api.support@cleartrip.com
They will ask your company details, business model and business case. If they are satisfied with those details then they will unblock your api key.
Since my project is for my final semester they have rejected my api key query.
Here i am sharing my java code. So that it might be useful for some one.
HttpClient client = new DefaultHttpClient();
String getURL =URL;
Log.d("URL",getURL);
HttpGet get = new HttpGet(getURL);
get.setHeader("X-CT-API-KEY", (my api key));
HttpResponse responseGet = client.execute(get);
HttpEntity resEntityGet = responseGet.getEntity();
if (resEntityGet != null)
{
Log.i("GET ", EntityUtils.toString(resEntityGet));
}
Since i was not authorized to use this api i got the following response.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><faults xmlns="http://www.cleartrip.com/apigateway/common"><fault><fault-message>Not authorized to access the service</fault-message></fault></faults>
HTTP URL is as follows
https://api.cleartrip.com/air/1.0/search?from=BOM&to=DEL&depart-date=2013-11-11&return-date=2013-12-12