One of the mechanics soon recognized Echo Papa from news photos — he was Erik Prince, founder of the private security firm Blackwater. Several of the Airborne staff whispered among themselves, astonished that they had been working for America’s best-known mercenary. The secrecy and strange modification requests of the past four months began to make sense. In addition to surveillance and laser-targeting equipment, Airborne had outfitted the plane with bulletproof cockpit windows, an armored engine block, anti-explosive mesh for the fuel tank, and specialized wiring that could control rockets and bombs. The company also installed pods for mounting two high-powered 23 mm machine guns. By this point, the engineers and mechanics were concerned that they had broken several Austrian laws but were advised that everything would be fine as long as they all kept the secret.
https://theintercept.com/2016/04/11/blackwater-founder-erik-prince-drive-to-build-private-air-force/