"Wir haben allerdings kein Fahrzeug."
I think it's safe to assume "allerdings" generally means "however". Especially when it is at the beginning of a sentence or introducing a subordinate clause:
Wir würden gerne wegfahren, allerdings haben wir kein Auto. (We would like to go/drive away, however, we do not have a car.)
Ich würde die Hose gerne kaufen, allerdings habe ich kein Geld. (I would like to buy the pants, however, I do not have any money.)
Mir gefällt das Auto, allerdings fände ich es in Rot noch schöner. (I like the car, however, I would like it even more in red.)