In "Quillber's Birthday Present", Zach Varmitech used a large grey blimp as his main form of transportation. The blimp was sufficient in cargo space and had cables for recharging a number of Zachbots, in addition to a large set of cargo doors and a staircase to the cockpit. Zach later rammed Martin with the blimp as revenge for ruining his plans, thinking that Martin was defenseless without any quills left on his Porcupine Power Suit. Unfortunately for Zach, Martin turned out to have one last quill on the suit that punctured the blimp after Zach rammed it, causing the airship to cartoonishly deflate and fly erratically.
The blimp hasn't been used since, presumably due to its exterior being easy to perforate.