Gullwing is the name of a craft in the original Wild Arms game and its remake Wild Arms Alter Code: F engineered by Emma Hetfield. It is also the name of a weapon in Wild Arms 4.
Wild Arms / Wild Arms Alter Code: F[]

The Gullwing in WA:F
Whenever the player boards the Protowing/Gullwing, the track playing in the background changes to Emma's leitmotif "The Bird Soaring the Sky" in the first game and "Wings of the Bird God" in the remake.
Protowing[]

Screenshot of the Protowing from Wild Arms
Named as the prototype of Gullwing, the Protowing was created using the EMMA Motor as well as the use of Zepet Roughknight's research; Emma can only complete it after the player party brings her the Gemini Circuit.
Wild Arms 4[]
Gullwing is a throwing dart in Wild Arms 4 meant for Arnaud Vasquez that can be equipped to him after crafting it from the proper regents at Jude's Workshop in Frontier Town Halim.