MILAN (Reuters) - Italian defense and aerospace group Leonardo LDOF.MI has invested in a company developing solar-powered drones potentially capable of unlimited flight with no refueling, it said.

The drone, which is expected to begin autonomous flights next year and go into production in 2021, can operate from existing airbases around the world and remain airborne for much longer than current aircraft.

Leonardo gave no financial details of the deal, but said it would become lead investor in and main industrial partner to Skydweller Aero Inc, and would lead marketing of the drone in Italy, the United Kingdom and Poland.

Chief Executive Alessandro Profumo said the deal would “improve the company’s competitive advantage in the aerospace business for the next 20 years”.

Leonardo said the system would comply with European export laws and would not be subject to international arms trafficking restrictions.

Development and construction of the aircraft will be carried out at the Skydweller facility in the Castilla-La Mancha region of Spain, Leonardo said. Its Aircraft division will help development and engineering via a dedicated team.

Various groups including Airbus AIR.PA, Boeing BA.N, Facebook FB.O and Google GOOGL.O have looked at solar-powered aircraft.

However, development has been hampered by issues such as installing solar panels that generate enough power for flight without adding too much weight to the aircraft.

Leonardo said Skydweller had already developed a “proven and mature” aircraft that had successfully circumnavigated the globe in 2016.

Its first development phase would focus on converting the aircraft from a manned platform to an “optionally piloted vehicle” by building in autonomy algorithms.

A second phase would develop a fully autonomous unpiloted aircraft, capable of standing up to a range of environmental conditions.

Drones capable of flying as long as the sun shone would have widespread applications in areas ranging from the military to communications, navigation, weather and environmental, and infrastructure monitoring.