The canopy was removable to allow the pilots to be swapped out. It also allowed the smaller two-seater canopy to be swapped out with the larger 4-seater canopy to create another variation of the ship.
For the episode "Happy Birthday Buck" we see a glimpse of the Star Fighter as it used to look 15 years prior.
Original models built/painted by: Mike Joyce & Ken Larson
TimeSlip Creations has built a Studio Scale resin garage kit of the Thunder Fighter for $314.95 (includes shipping)
MonstersInMotion.com is producing a limited run (200 only) of Thunder Fighters, said to be cast off an original miniature for $749.99
One of the Original Thunder Fighters on YourProps.com owned by "cylon02"
Original Thunder Fighter Canopy on YourProps.com owned by "bubblejumper"