the first russian fully electric manned sigma-4e aircraft at the maks-2021 international air show in zhukovsky

2021 air aircraft airplane aviation battery blue building business central ciam city civil commercial demonstration display double eco ecology electric element engine esu exhibit exhibition experienced exposition field first friendly fully institute international july light maks2021 manned max modern moscow motor plant power propeller region russia russian salon sample screw show sigma sigma4e sky space sunny transport zhukovsky