If you're VERY flexible, living in the UK, wanting a trip to the USA to see family and friends, and getting broadband soon anyway, it could be a good offer. But it is restricted.
I had a look at the site - it's to New York, Atlanta, Boston, Washington DC or Philadelphia only, and you have to tell them two months you can go, and three possible destinations. No travel to USA in July and August, must book 45 days ahead. Even with giving them three airports and two months there doesn't seem to be any promise that they'll have availability - indeed, they suggest you book early as popular destinations will go fast. It's ONE seat - you can buy a second at 219 pounds + Tax & insurance.
Broadband must be ordered by 20 June and installed by 18th July.