seperate or combined prices

Currently checking sale price flights on the website for journeys to Denver in late May. The VS website suggests UC return prices of £2964.96 on the days I require but if i book separate legs with Virgin to New York and then Delta from New York to Denver, the price is £2496. Is this common? Shouldn't the website price be the sum of the two legs?

Furthermore, the website does not even show VS 111/VS112 flying to New York under the combined VS/Delta journey to New York/Denver but I can assure you these flights do exist!

so, just checking when traveling to the States is this common?Should i simply ignore the Virgin website and book each leg separately?

Yes it is quite common for multi-sector trips to be cheaper booked separately than as one ticket.

The down side of booking separately is the loss of delay/cancelation protection.

E.g. on your return from Denver to NYC, if the Delta flight is delayed and you miss your VS sector, neither airline has to get you home, and you could end up buying a new ticket to get home.

(AA have a very generous policy when it comes to connecting to/from OW flights on separate tickets!)