Inside the package is a small, strange gadget. And a note.
This is a small cloaking device for your ship. Well, bus. Well, car. Modeled out of the TARDIS's systems, so you won't actually be invisible (can't have you pretending to be Wonder Woman as well as Thomas Crown), you'll just vanish from typical radars and from obvious detection. People will just want to look away from the car, rather than look through it. Just attach it below the wheel, the intelligent chips should recalibrate the core of the car while you're in-flight.
PS: Don't try to modify it for a body suit, eh?
PPS: Up for tea, while I'm in the area?