outsider8u Welcome to the forum
If not flying often often better to buy flights on price and/or convenience and not any freq flyer miles you may (or may not) get. With airline alliances/partners you can travel on 1 airline, but collect miles to another, subject to the FFP's terms & conditions. FFP's are for the long term: not just a few random flights
US Airways and AA have merged. Will be known as AA and part of the OneWorld alliance. In time your US Airway miles will become AA miles. Details & dates have not yet been published by AA. But it has been stated conversion will be 1 to 1.
If you now travel the world also worth joining a Star Alliance airline FFP. Despite the recent miles devaluation, United is good for many living in the USA
Alaska is also a good FFP with many partner airlines.
http://www.alaskaair.com/content/mil...ePlan-partners