Really, don't worry. Buying from expedia is practically no different than from the carrier direct once you are at the airport. I use expedia.co.uk all the time for bookings and have never had a problem yet. In fact I have found them excellent, especially when forgetting to charge change fees! 65 flights so far this year and no problems yet... touch wood.

Enjoy the cash saving and all will be fine!

As for travel insurance, it is an ABSOLUTE MUST for those travelling to the states from the UK. The astronomical cost of medical treatment and the liability (sue sue sue) aspects are the reasons why. Try to buy from an internet site rather than overpriced travel agencies. I normally pay £60 for a years worldwide insurance.