UK to USA flights. Cheaper to book (a year) in advance or at the last minute?

[Stellaaaaa]

Just flights as staying with friends.

Its cheaper to book in advance rather than last minute.

I find much cheaper taking advantage of deals in advance.

depends - are you a family travelling together or are you a single traveller? What time of year are you going?

If a family in the summer, sooner rather than later just to guarantee seats

single traveller out of school holidays it's always worth waiting for flight sales (eg ANZ currently have a sale LHR-LAX)