How do you get the aurora ticket on Pokemon fire red?

You can't get the Aurora Ticket in Pokemon Fire Red.

The Aurora Ticket is an item found in Pokemon Crystal, Gold, and Silver, allowing you to access the "Whirl Islands," a small island chain north of Ecruteak City.

Fire Red, a remake of the original Pokemon Red, does not include the features from the second generation games, like the Aurora Ticket and the Whirl Islands.