OK, here is the AA scoop. AA has electronic upgrades in addition to stickers. I only use electronic. When you receive awards, your account is automatically credited. You may purchase more upgrades in the flollowing ways:

* Over the telephone using a credit card (e.g. when making bookings).
* At the counter when checking in.
* At the Admiral's Club (if you are a member).
* At the Platinum Service Center (if you are a Platinum or Exec Platinum Member.

Upgrades normally run $35/segment (i.e. 500 miles), but if you buy 8 or more at once, they are $25/segment --> what a deal, it is like getting 3 for free and some change! This is a promotion, but has been running as long as I have lived in the US.

You can upgrade companions from your account too. When flying Reno Air, I ask the agent to print out some upgrades and hand those in to the Reno agent.

Hope this helps.

TCrazy