Russia’s invading forces had lost three airplanes and as many helicopters over April 21, worth upwards of USD 105 million combined.
Here is an estimated cost of the types of Russian aircraft shot down from the skies over Ukraine on Thursday, April 21:
Read more: Russia Used its Newest Su-57 Stealth Fighter to Bombard Ukraine with Aging, Soviet-Era Kh-59 Missiles
Fighter jets
• Su-34 - ~$ 40 million,
• Su-35 - $ 32 million,
• Su- 25 - $ 11 million,
Helicopters
Ka-52 “Alligator” - $ 16 million
• 2x Mi-8s - $ 3 million each.
According to Ukraine’s Operational Command “East”, air force units, assisted by JFO forces operating outside of Kharkiv, attacked and shot down two fighter jets -- a Sukhoi Su-34 (on which Defense Express already reported) and a Su-35.
Both had been shot down nearby Izium from ~20,000 feet (6,000 m) altitude.
OC “East” also reported on the downing of a Russian Orlan-10 drone over a location outside Kharkiv.
Moreover, UAF General Staff has reported that an enemy Su-25 fighter aircraft and another Orlan-10 UAV had been shot down with, respectively, Stinger and Starstreak missiles by air defense solders from Ukraine’s Air Assault Force.

National Guard’s air defense soldiers have reportedly shot down a most advanced Russian Ka-52 "Alligator" helicopter gunship using a MANPAD.
One of the enemy's Orlan-10 UAV of four that were shot down by the Ukrainian Air Assault Forces:
Further to this, two Russian Mi-8 helicopters had been fallen down.
April 21 was a bad day for Russia’s air force but a great day for Ukrainian air defenders.
Day-end update: The number of drones – all of them Orlan-10 medium-range multi-purpose UAVs -- lost by Russia over April 21 has increased to nine, according to Ukraine’s Air Force.
Defense Express reported that April 21 was a good day for a hunt for Ukrainian paratroopers - four russian 'birds' down.

Read more: Day 58th of War Between Ukraine and Russian Federation (Live Updates)