A combination of “flug” (flight) and “eldur” (fire). Flight fire! But that isn’t all. If you’re a rocket scientist, you’re called a “flugeldur vísindamaður.” “Vísindi” (science) and “maður” (man/person) added to flugeldur makes that a flight-fire science-man. (Or if you’re a woman you can go ahead and call yourself a flight-fire science-person).
(It may be true that flight fire in essence means fire flight, as a better interpretation).