I think Foghorn has summed it up nicely, Serco is a massive organisation, and its highly unlikely that the IT bods will have the remotest idea of who or what Serco Aviation are all about.
Even if there could possibly be some collusion between the two, it would be so obvious that the Aviation division wouldn't survive to see another day.
Whatever the conspiricy theories, I doubt that the passing of commercially sensitive data between the two would ever happen, as that now carries very serious legal implications, along with long prison sentances.