Wingspan's ability can put cards Upgrades scrapped from him under him. What does this mean?
[Source: WotC]
The cards under Wingspan are basically out of play and are used to count the bonus for Wingspan's alt mode ability. They're not considered on the battlefield, even if that's where they are physically, so none of their abilities apply. Those Upgrades aren't on Wingspan, and so on. They're also not in your scrap pile, so they won't be shuffled into your deck when it's empty.
The
Battle Master upgrade is put into the KO area, then Wingspan's trigger puts it under him and counts towards his alt mode ability. When Wingspan is KO'd, the card is placed into the KO area.