Welcome to (posting on) FT,
belfastgt!
Originally Posted by
belfastgt
I have 18,000 miles in my BA Avios account and I would like to put them to the best possible use in upgrades.
18,000 Avios isn't going to get you very far. Perhaps the best use of them is for two short round-trip short-haul tickets, assuming that you have collected at least one Avios in the last year and therefore qualify for Reward Flight Saver pricing.
Off the top of my head, I think that you can't use Avios to upgrade a cash ticket on Aer Lingus.
I suspect that you're going to be pretty hard pushed to find any BA long-haul route on which 18,000 Avios would get you an upgrade to business class. On the short trans-Atlantics (eg London to New York), you'll get an upgrade from a paid-for business class ticket to First, but that does depend on you buying that business class ticket with cash first. See this chart, from
this post:-
