Paragon VTOL Aerospace launched the T21 Raptor hybrid aircraft program in 2018. In March 2020, the company indicated that it intends to achieve a first flight by the end of the year and achieve type certification by the end of 2021. It says that it has been conducting "virtual" simulated testing while building its first prototype. Before the prototype T21 flies, it intends to conduct further tethered flights using various unspecified aircraft to evaluate the technology behind the T21. The company says that it has assembled a fleet of small drones and various larger eVTOL designs that it has acquired from other start-up ventures. It intends to conduct initial testing in a warehouse in California. In March 2020, it reported that a full-scale prototype of the T21 is under construction