Several of Defense Express's own sources immediately revealed this trend at the front - the Russians began to "save" their front-line aircraft, using their planes and helicopters only in the directions of the main strike. While in the secondary areas, the occupiers are trying to "do without" missile strikes using air cruise missiles or tactical ballistic missile Tochka-U (NATO reporting name is SS-21 Scarab). The enemy is doing this because he is afraid of the Ukrainian air defense.

In particular, according to Defense Express, on Thursday, May 26, 2022, the invaders fired as many as 10 Kh-59 Ovod air-launched cruise missile at targets in settlements in Donetsk and Kharkiv regions.
Read more: Summary of May 27, the 93rd Day of War: Successful Ukrainian Air Raid and Numerous Russian Casualties
The next day, Friday, May 27, there will be two Kh-22 air-to-surface missiles and seven Tochka-U tactical ballistic missiles at facilities in Donetsk and Luhansk oblasts.
Also for strikes on the Lyman and Avdiivka during May 27, the occupiers made 19 sorties, operating at an altitude of 6-8 kilometers.

From this we can draw the following conclusions:
During the war against Ukraine, the russians finally developed a "Stingerfobia" and a fear of Ukrainian air defense forces. Because of this, the enemy uses either tactical ballistic missile systems or air-based cruise missiles to strike targets in the frontline, which are out of Ukrainian strike and air defense systems.
In addition, it can be stated that in order to avoid the defeat of MANPADS used by Ukrainian troops, the russians are ready to "sacrifice" the accuracy of bombing, and fly at altitudes of 6-8 kilometers. It also suggests that Ukraine does not have enough means of air defense at the frontline to "get" russian aircraft at altitudes of more than 5 kilometers.

Defense Express reported early on how many missiles russia already used against Ukraine.
Read more: Air Defenses vs Unmanned Aerial Vehicles