Skies of Arcadia

Can you beat glacian on the train in vaula?

Just out of curiosity, if you were to max out the levels of vyse and aika before the fight, could it be done? and if so what happens?

No, it's not possible. Skies' does that numerous times with different enemies throughout the game. Galcian will kill your characters in one hit, and even if you raised your levels he'd still pretty much beat you easily.