There are hidden locations accessible with the airship by using the input feature in the airship. Here are the passwords...

Password #1: GODHAND
Input this in all capital letters to reach the ravine below Mushroon Rock Road, and Rikku's legendary weapon is in a treasure chest at the top of the area.

Password #2: VICTORIOUS
This password opens a secret location in the Besaid ruins. Climb up the tree branch to obtain Rikku's Victorious armor.

Paassword #3: Murasame
This password opes another secret location at the Besaid ruins. Cross the platform to find Auron's Murasame.

Airships Location
1. Omega Ruins - [X: 67-75 / Y: 33-38]
2. Sanubia Temple - [X: 12-16 / Y: 41-45]
3. Besaid Falls - [X: 29-32 / Y: 73-76]
4. Baaj Temple - [X: 11-16 / Y: 57-63]
5. Mi'hin Ruins - [X: 33-36 / Y: 55-60]
6. Battle Site - [X: 39-43 / Y: 56-60]