Ever since Air Canada spun off its frequent flyer program a decade ago, the big financial revolution in loyalty that never happened was taking mileage programs public.

Much larger programs than Air Canada’s were believed to be able to command tremendous valuations, at the time some said United’s MileagePlus was worth $15 billion as a standalone entity.

Several programs separated their loyalty arms into separated businesses without actually turning those public. They were prepared to do so, but most didn’t.

Qantas was expected to take their program public in 2008. They didn’t. The thought came up again as Qantas struggled in 2014. But they didn’t. Stockholders pushed American to do it in 2007. It never happened. One analyst argued rather than being a windfall for airline shareholders, the value of airline stocks largely reflected their loyalty business and so the spinoff wouldn’t net dollars to investors.

As I wrote when Lufthansa prepared to spin off Miles & More,

In general spun-off programs which aren’t wholly-owned by their associated airline tend to bifurcate, serving the loyalty needs of an airline and also as an all-purpose loyalty program aimed at a mass audience of its non-flying members. A move of this sort likely puts Lufthansa more firmly into the broader loyalty game, focusing on the bulk of its 20 million members rather than predominantly on its frequent travelers.

To me it underscores how far frequent flyer programs have come over the past three decades — they’ve been the most successful marketing innovation likely ever — and a majority of miles are no longer earned directly by flying. That’s why, eventually, frequent flyer programs will be back in front of the Supreme Court, so that state contracts claims will no longer be pre-empted by the Airline Deregulation Act.

Some programs have taken outside investment. Where Etihad faces foreign ownership restrictions in the airlines they’re investing in, they’ll take an outsized stake in a related frequent flyer program.

Aeromexico has outside investment from Aimia, the company which took Aeroplan public and the folks behind many of the efforts around the world. Aeromexico has been rumored to be doing an IPO for some time.

Some new details emerge, via Bryan S.:

Grupo Aeromexico SAB is working toward an initial public offering of its frequent-flier rewards program that would value the business at about $1 billion, according to two people with knowledge of the matter.

The probable timetable for an IPO involving part of Premier Loyalty & Marketing SAPI is 2017, said one of the people, who asked not to be identified because details aren’t public.

Aeromexico currently owns 51% of their frequent flyer program, and Aimia 49%. No doubt Aimia is looking to cash out on their investment.

Two relevant questions for such spinoffs are whether the programs are worth more to investors, or to their affiliated travel company? And whether the program remains as valuable once it spins off.