1959, from ultra- + light (adj.1). As a noun meaning "ultralight aircraft" it is recorded by 1979.
ultimatum
ultimo
ultra-
ultra vires
ultra-conservative
ultralight
ultramarine
ultramontane
ultranationalism
ultrasonic
ultrasonography
)window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}