If you will continue to travel with some frequency in Economy Class, you might find it more advantageous to fly on carriers that will enable you to earn status in, say, Star Alliance or oneworld. Note that you do not have to credit a flight to the FFP of the carrier you are flying. For example, flights on AA, BA, or JL can be credited to any of those carriers, or to any other oneworld carrier. Crediting such flights to, say, Iberia Plus, might get you mid-tier elite status pretty quickly; that would entitle you to lounge access, Main Cabin Extra seats, free checked baggage, and other benefits when flying AA in Economy. Getting status on AA would not get you lounge access, but would entitle you to upgrades (when available) when flying AA in Economy.