I have gotten the air ship after beating yunalesca. It says that if you beat the last nagi hill race you will get something to upgrade Tidus weapon. I dont know what nagi hill is and I beat a race at calm lands and all it gave me was a sun sigil. need help
do you have the sun crest?
You get the Sun Crest after killing Yunalesca. It's in a chest.
The Sun Sigil can be won from the Chocobo race. You have to receive a time of 0:00 to get it. It's very tricky, and can be quite frustrating, but it is possible. I've done it.
The Caladbolg (Tidus's ultimate weapon) is near the top left of the map in the calm lands. Remember that guy who was standing in the way of a path and wouldn't let you pass? Well, now that you have both the sigil and the crest, he will no longer be there. Go down that path, explore, and use the celestial mirror to get the Caladbolg.