Zarhym has confirmed on the official forums that a new heirloom item called Tome of Cold Weather Flight is planned to be added in patch 3.2 that allows your alts to learn Cold Weather Flying at level 68. You can only purchase the tome with a level 80 character on the same realm, faction and account to mail to your alts. Each tome costs 1,000 gold and is consumed once it's used. "It's a small perk for those who have reached level 80 and like leveling new races or classes," Zarhym said.
As always, the functionality of the tome may change as testing progresses. You can discuss the topic in this thread in our general forum and read Zarhym's original post below.