I think you are getting Avios mixed up with Avios, or even Avios

If you look at the country selector you will see that this flavour of Avios is not available in the USA

https://www.avios.com/country-selection

That Avios is a loyalty scheme with affiliates in the UK, South Africa, Spain and Italy. There is no way of earning them in the USA

If you want to join British Airways Executive Club then go to www.britishairways.com

If you want to join Iberia Plus then go to www.iberia.com

The currency of both of the above is Avios