The Pottier P.50 Bouvreuil ("Bullfinch") was a single-seat, single-engine racing aircraft developed in France in the late 1970s and marketed for homebuilding.
Two ships of the United States Navy have been named USS Bullfinch, after the genus of European finch.
Danny uses a computer that Professor Bulfinch has created for NASA to prepare his homework, despite Professor Bullfinch's warning that Danny is to leave the machine alone.
Prof. Bullfinch is able to use this altered material to create ISIT (the Invisibility Simulator with Intromittent Transmission), a dragonfly-like probe which could be piloted with a Telepresence helmet and gauntlet gloves.
It carries an inscription, including a poem, bewailing the death of a bullfinch.
There are over 70 different kinds of bird, including Kingfisher, Dipper, Sparrowhawk, Kestrel, Song Thrush, Bullfinch, Grey Heron and Blackcap.