Koopa Cruiser

The Koopa Cruiser is Bowser's personal airship. It was used in Mario & Luigi: Superstar Saga to transport Mario, Luigi, and Bowser to the Beanbean Kingdom. After the battle against Fawful, the Koopa Cruiser crashed down to Stardust Fields. The Cruiser (in a poorly-repaired form) was later used by Bowletta to capture Princess Peach, who turned out to be Luigi in disguise, although their attempt at doing so was unsuccessful as Luigi, stalling them with help from the Koopa Cruiser's Pinch Crane, managed to not only escape but also return the Beanstar to Beanbean Castle.

The Koopa Cruiser was used again in Mario & Luigi: Partners in Time to evacuate Baby Bowser, Baby Mario, Baby Luigi, Baby Peach and the young Toadsworth from Peach's Castle after it was attacked by Shroob UFOs. The Shroob UFOs attacked the Cruiser, forcing it to drop altitude over Hollijolli Village. Baby Bowser is coaxed into into rescuing Mario and Luigi from the Shroobs and the Bros. are brought aboard. As the Cruiser flies over Peach's Castle, which had been captured by the Shroobs and was then called Shroob Castle, Princess Shroob launched a missile that shot down the Cruiser sending it crashing into Bowser's Castle.

Oddly, in Mario & Luigi: Superstar Saga, Bowser said the Koopa Cruiser was his new weapon, but he had used it in the past. Another thing that doesn't add up is when the Koopa Cruiser crashed into Stardust Fields one of the Koopas will say that they hadn't finished paying it off; though it's possible that this was a new version of the Koopa Cruiser, considering the one Baby Bowser had owned crashed into his castle in the past.