How does it all work
 

Hopefully this post is in the correct place.

UK resident and for the last 10 years I have been following England's cricket team. When they play somewhere nice (Aus, NZ, Windies) then I go, if no cricket I go to SE asia. Additionally I take a second break each year to the Canary Islands.

I'm looking to cut down on my working time as a lead up to early retirement, and take more overseas holidays. I am not signed up with any FF schemes but thought that given my likely increased airline spend (including flying J for my main hols) I should register somewhere. I know there is another thread where you can get advice on which FF programme is best for you, but before posting there I would like to understand how airmiles / tier miles work.

When I see people saying that they upgraded to F on an Etihad flight using Alaskan air miles, I think how does that work. Is there a post somewhere that explains how the system works and who's miles you can use where?

I don't think there's one post that will explain the whole thing for you. There are tons of "which FF program is for me?" stickies and long, long threads on this topic for nearly every major city and region.

Every airline has alliances (routing and codesharing networks) with other airlines, the big ones are Star Alliance, SkyTeam, and Oneworld. This means you can use their miles for awards/routings on partners. Most airlines also have one-off bilateral deals with other airlines (e.g., the Alaska-Etihad partnerships you mentioned above) independent of the alliances. This means there's no single place to search for award travel, and, in fact, the system is byzantine and opaque and surprisingly fragmented. As you might expect, airlines don't make it easy for you to get great value out of your miles/points. At least not in the sense of aggregated, transparent search tools. Probably 50% of this entire site is dedicated to hacking through that opacity and scheming to get the available upgrades and awards. Most people on this and similar boards have (best guess) a couple hundred hours invested in finding the right airlines to be loyal to (for their specific needs, preferences, and location), configuring their accounts for maximum earning, finding the right mix of credit cards for signup bonuses vs. fees vs. earning rates and other card benefits and privileges. To further complicate matters, credit card issuers then have bilateral transfer partnerships with a subset of airlines from each of the alliances (i.e., Amex points transfer to one group of airlines, Chase points to another group, with small pockets of overlap).

If I were in your shoes I'd start by reading this site and some of the Boarding Area blogs to make a shortlist of credit card signup bonuses to go after and get familiar with some of the basic concepts (partnerships, alliances, awards vs. upgrades, transferable CC points vs. airline miles). There are many mile-earning strategies but CC signup bonuses are the simplest to start with. I would also scan the departures page of Heathrow and Gatwick (or your other preferred UK airports) to look for direct flights to the destinations you care about, taking note of which airlines go there and THEN which alliances they belong to. View from the Wing (blog) is very good for summarizing the various technical limitations of all the airline search engines.

Most people who put any time into this end up with a portfolio approach, that is, a smattering of airlines and hotel chains as well as credit card issuers (with points transferable to those airlines or complementary partners) suitable for their taste and geography. Good luck! Welcome to a weird-... hobby. Only the homework part should be serious, the rest should be fun.

Alaska airlines miles cannot be used to upgrade anything but Alaska Airlines Flights

Alaska airlines does not have a partnership with Ethiad.

They do have a partnership with Emirates where you can book a first class award ticket but all Emirates Awards with Alaska Airline miles must start or end in North America. Cathay pacific Award using Alaska miles will get you to Hong Kong but you will have to book a separate ticket on from there.

Thanks for the detailed response.

I was hoping things would be simple, but obviously not. Further reading needed.