The design and adjustment of a twin-engine aircraft with flight weight of 11.5 kg, capable of carrying a payload of up to 3 kg over a distance of 70–80 km, based on the Pixhawk 6C flight controller using the Arduplane ver.4.3.7 firmware was carried out. The experimental adjustment of the firmware parameters for a given UAV geometry, its weight, and propeller-motor group was performed, ensuring a stable flight when performing an automatic mission. The parameters of the aircraft’s automatic takeoff for a mission flight were set. Despite the relatively large weight of the aircraft (up to 11.5 kg), its launch is configured by hand in automatic mode by one person without using a catapult. The designed aircraft is configured in the advanced fault-tolerant configuration (AFC) mode that is able to ensure the return of the aircraft to the launch point in the conditions of electronic jamming systems (EJS). According to this mode, if communication with satellites is lost, the aircraft stops follo-wing the planned mission and switches to a backup flight trajectory, which is able to take it out of the EJS zone. In this case, the simplified route is performed using the inertial system until the satellite communication is restored. The efficiency of using two-band GPS receivers with the installation of antenna screens to counteract electronic countermeasures is experimentally demonstrated, even in conditions of their close location to a flying drone. The paper considers different types of three-band antennas, including ceramic, helical with a screen, and helical antenna arrays.