Ukraine war: Air defences shot down the drone near the Engels base, but falling debris fatally wounded three technical staff, the defence ministry said.
Earlier this month, Russia accused Ukraine of a similar attack on the airfield, home to bombers that have carried out missile attacks on Ukraine.
The base lies about 650km (400 miles) north-east of Ukraine’s border.
The Ukrainian military did not officially admit to the latest attack, but air force spokesman Yuriy Ihnat said the explosions were the result of what Russia was doing on Ukrainian soil.
Hours afterwards Russia’s FSB security service announced it had killed a four-strong “sabotage group” trying to enter the Russian border region of Bryansk from Ukraine armed with improvised explosive devices and German-made submachine guns. The FSB released video of what it said was the “liquidation” of the group, although there is no independent confirmation of the incident.
