Not counting promotional miles, just miles for elite bonus or class of service bonus.

For example, as top tier elite on Air France, I earn 100% bonus miles on all flights. LAX to anywhere in Europe (outside of France) is around 6500 miles one way = 26,000 miles round trip in Economy (with my 100% bonus). A free ticket from LAX to anywhere in Europe is 50,000 miles. So it takes me two paid trips to earn one free trip. This probably gets to be easier on a mileage run, but I was thinking of more “normal” routings (i.e. no more than one “unnecessary” stop). Are there any routes where you can actually earn one free ticket (in the same class of service) for each paid ticket? Since this relates to earning miles and tickets with miles, I thought MilesBuzz! was appropriate.