It is a dark blue truck with money bag logo on it's side.
Breaking the BankEdit
On the way to the bank, the truck was driven by Winston Davis and Ted McAdams, who were probably going to transfer money into the bank. When they stopped, Winston put Henry in his disguise bag into the truck. Later he was arrested for kidnapping. (As said by Phoenix Wright in the trial, and later confirmed in military book in the beginning of Infiltrating the Airship).
Escaping the PrisonEdit
When Henry slides down the prison building by the rope, he gets hit by an armored truck, possibly the exact same one he used to get into the bank.
In the legal ending, when he comes out of city hall after his trial, the truck drives past him on the road and Henry starts chasing it, celebrating his freedom and indicating that he's not done with crimes yet.