I'm not expecting many people to be interested in this one, but a friend asked me to find business class flights in Easter for New York and for anyone who knows normal prices of business class flights to New York from the UK, you are talking around £1400pp at least, more if you want to avoid the likes of Ukraine Airlines. To get a trip that is 2 nights in Madrid and 4 in New York with all your flights and the long haul business class is a bargain, in my opinion. You are probably saving around £700 minimum pp by flying from Madrid and you get a lovely city break in Madrid too.
This trip involves you flying from London to Madrid with British Airways (13th April), so luggage and food/drink are included. You will then stay in Madrid for 2 nights. There are plenty of cheap options in Madrid, and I was tempted to put an Ibis hotel in this deal, but I decided to pick the Holiday Inn. I've stayed here myself on the way to Chile (albeit was only about £21 a night then) and I found it really convenient as they have a complimentary airport pick up and drop off, which is ideal if you have luggage and its really easy - and cheap, to get to and from the city to go and enjoy some chocolate churros!
NB - If you have Avios, you could book a reward flight to and from Madrid cheaply, or use your Avios to upgrade your flight to business class to and from Madrid.
On 15th you will fly to New York for 4 nights. I've chosen the 4* central New York Westin Grand Central as it's convenient, walking distance to attractions such as the 'top of the Rock' and Empire State Building. You could reduce your cost by staying in hotels outside of Manhattan itself.
On 19th you'll fly back to Madrid and then recheck in for your flight back to London.
British Airways flights from London to Madrid for 2 £174.02 book at British Airways.
2 Nights in Madrid at the Cala Alcala Holiday Inn £109.84 book at Trivago (hotels.com)
Book 2 x business class flights from Madrid to New York return Euro1864.12/£1587.58 book on Delta Airlines Direct
4 Nights in 4* central hotel in New York £599 book at Trivago