Hummingbird Z7 are wings, designed by Opal Koboi. They have solar panels, creates no sound and has power to fly two times around world. In book 1, Artemis Fowl, Holly is weary about how LEPRecon gets always old ready-to-scrap-yard things. But after fight with Troll and discovering that her magic is too low to even make shield, she takes Hummingbird Z7 and flies with them to Ireland.
Foaly wouldn't want Holly to fly with Hummingbird, because it is not his invention and is annoyed because of it.