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 while the Mario Bros. and Bowser were temporarily working together. 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. It is unknown what happened to the Koopa Cruiser after the events of the game - it is likely it returned in Bowser's possession.

Another Koopa Cruiser appeared 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 a version of 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 an entirely different Koopa Cruiser, considering the one Baby Bowser had owned crashed into his castle in the past and was never repaired. The main reason why this happens is Superstar Saga released before Partners in Time.

Bowser Baddies are said to be Bowser's handpicked troops that help pilot this airship.

trivia

 * In Mario & Luigi: Superstar Saga, (adult) Bowser shows off the aircraft as his "latest invention". However, in Mario & Luigi: Partners in Time, Baby Bowser is shown to have owned the same Cruiser far back in the past.