Flying Mount in Northrend?

On WOW how can you use a flying mount in Northrend? I assumed you needed the Epic mount but ive seen a number of players with TBC mount 150% flying around.

You need cold weather flying first

1000g can be bought at level 77

If you already have a lvl 80 (i think you need to be 80) you can buy the book to learn flying mounts in northrend and give it to another char on your account who can use it at lvl 68.

If you already have a level 80 You can buy "Tome of Cold Weather Flight" for 1000g and send it to your other characthers, can be used at level 68