After the successful inaugural event in November 2020, the rules for the 99++ Luft Balloons April 2021 have been announced and will be hosted by Indiana University again. Naval Research Laboratory, the University of Los Angeles and California, Penn State ARL, a collaborative team between Penn State and Army Research Laboratory, George Mason University are the four teams taking part in the competition. IU Crane has dropped out of the event due to logistical issues.