Sorry but I think you will have to put this question to a cruise agent to get the full answer. Yes, it is possible, you would normally arrange with the agent with whom you made your booking or intend to book to make out your flights from Glasgow to New York two days early and then from Southampton to Glasgow. Your agent can arrange for a hotel in NY as part of the deal or you can arrange your own hotel in which case you will probably have to arrange your own transit But primarily talk to your agent and if the Victoria Travel or (cruise.co.uk) are unsuitable then try Scotia Travel in Glasgow who specialise in flights from your city Hope that helps....Nei.
I also live in Glasgow and my family and I have booked passage on the eastbound trip on the QM2. I am flying to Newark with Continental on a direct flight from Glasgow. I am staying for 7 days in New Jersey prior to the sailing, I have made my own arangements regarding my hotel in New Jersey. I booked through Barrhead Travel who can offer accommodation in the states prior to your sailing. Hope this helps.