how far ahead do you know how full a flight will be?

[sometime_flyer]

I flew VA in PE in Apr this year. Its not Business Class by any means - obviously - but very good nonetheless with pre-departure drink, good legroom and hip room. Meals were served on ceramics with a proper tablecloth and a nice choice of wines to boot.
One downside is the armrests don't raise so there's no using empty adjacent seats if there happens to be one. Good luck finding an available seat to upgrade too...in Dec!