Launched May 1 , 1981 , it was the second such loyalty program in the world ( after the first at Texas International Airlines in 1979 ) .
Launched May 1 , 1981 , it remains the largest with more than 67 million members as of October 2011 .
Launched May 1 , 1981 , it was the second such loyalty program in the world ( after the first at Texas International Airlines in 1979 ) , and remains the largest with more than 67 million members as of October 2011 .