Shed, with respect the whole point of the 22 committee is that it doesn't merely 'voice the party line' (indeed it didn't even permit frontbenchers to attend until 2010); it represents the views of backbenchers (often the best local campaigners). A third runway at LHR is about as popular as a cup of cold sick amongst a significant number of Tory MPs, and if he was merely interested in politicking then he probably wouldn't voice a locally unpopular view in public.