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

The hybrid-electric Raptor is an optionally piloted vehicle intended for a variety of purposes, including cargo transportation, air taxi services, agricultural support, law enforcement, and military missions.

Siemens is providing software to help Paragon fast-track the development of the technology behind the T21 Raptor, in areas such as conducting stress tests and assessing heat variances. The University of Florida is working with the company to advance the use of plasma in reducing noise generated by drag. Paragon holds five patents associated with plasma technology. Robert Frederick, founder of logistics group Sirqul and a co-founder of Amazon Web Services, is involved in developing software for Paragon's planned unmanned traffic management (UTM) system to support eVTOL aircraft operations. Paragon founder Dwight Smith told FutureFlight that the company intends to offer a "virtual highway platform" to manage traffic flow for autonomous aircraft and that this technology will be made available to other aircraft manufacturers and operators. He said that this UTM system will incorporate technology already used in autonomous cars. 

Paragon says it has had discussions with both Safran and Rolls-Royce and expects one of them to provide the engine for the T21's hybrid electric powerplant. The company intends to manufacture the aircraft itself, but says it is also in talks with a leading automobile manufacturer about possible involvement in the program. It has secured a 12,000-acre site in Jamaica that will be used for production facilities. Smith predicted that Paragon will employ as many as 2,000 people in Jamaica by the end of 2021 as the program transitions from development to operations. Initially, he expects the aircraft to be used for cargo-carrying roles before passenger flights get underway.

In mid-2021 Paragon dropped the T21 Raptor design in favor of a new model called the Paragon Soar. The company also appears to be working on a single-seat, all-electric eVTOL model call the Paragon Dragonfly that would have a flight time of just 25 minutes.

As of late 2022, the Brownsville, Texas-based company was indicating projected type certification and initial deliveries during the third quarter of 2025.  It said that flight testing of a full-scale prototype would get underway during 2023. The new design shows eight ducted fans, six of which are part of the wing, with the remaining two attached to the tail and apparently intended to tilt for cruise flight. There also appear to be multiple smaller ducted fans in the wing. Paragon says the aircraft will be able to carry eight passengers and a pilot and be able to fly at least 500 miles. When announcing the new model in 2021, the company indicated that it intended for the engines to run on hydrogen, but since then the range projection has increased and it is not clear what fuel the vehicle will on entry-into-service. According to specifications at the Paragon website, each ducted fan will have a 1,000-hp electric motor.