The step by American makes it likely that other airlines will follow suit.
As of last Monday, no other airline had followed suit.
The airlines are following the rules as they have for the last 15 years, before the agency's recent statement on the subject.
As of yesterday, he said, no other airline had followed Northwest's lead.
Following are the 15 largest domestic airlines and their hubs.
Many airlines immediately followed, but others did not, and the new system crumbled.
And it is not clear that other airlines will follow.
Several European airlines quickly followed with their own transatlantic services.
Now, airlines, in case you haven't noticed, don't follow the free.
As expected, the other major domestic airlines soon followed suit.