To obtain the Light Wing Dragon (Laser Level 6), you must first free the infant dragon from the Shellcoof Genesis Chamber after mutating to the Eye Wing Dragon (Laser Level 4). Let the story progress until your dragon reaches Laser Level 5 (somewhere near the end of disc 4) and return to the map location, Above the Ruins. Fly your dragon down the left branch of the canyon until you reach the roosting birds and wait until the infant dragon flies off the top of the screen.

Fly on a little farther (about 5 seconds or so), and turn around and fly back until you can target the infant dragon. Upon accessing the infant dragon, you will chase him, and the birds around the canyon a couple of times until the birds enter a small, secret cave. Enter the cave to reveal the birds' nest. One of the pyramids in the nest area contains the mutation up to the Light Wing Dragon.

Now you can access the crashed ship in the desert area and get a new Special Class berserker spell, as well as replace the Dragon Crest in the Red Ruins to change into the Solo Wing Dragon. Warning: once the Solo Wing Dragon is obtained, you will no longer have access to the infant dragon. So fly around a bit in the other map areas to get the hidden items he helps you find, beforehand.