Now that the plane has arrived at the intended destination (Vilnius), it was missing two Belarusian citizens (Protasevich, and presumably his girlfriend who was on the flight has also been arrested) and four Russian citizens. There are some rumors that those four people were trailing Protasevich before the flight and were involved in the 'bomb threat', so it might as well have been a common Belarussion-Russian operation, but as of now it's all just guesses and speculation, perhaps tomorrow we'll have better info.
Russia benefits politically, too - sanctions will be imposed by the West now, driving Belarus closer to Russia.
It underscored that with the support of President Vladimir V. Putin of Russia, Mr. Lukashenko is prepared to go to extraordinary lengths to repress dissent....
In Russia — where the state media described last year’s uprising against Mr. Lukashenko as a Western plot — the arrest met with approval among Mr. Putin’s supporters. Margarita Simonyan, editor of the pro-Kremlin RT television network, wrote on Twitter that Mr. Lukashenko “played it beautifully.” And Vyacheslav Lysakov, a member of Parliament allied with Mr. Putin, described Mr. Protasevich’s arrest as a “brilliant special operation.”
https://www.nytimes.com/2021/05/23/world/europe/ryanair-bela...
In earlier cases with genuinely surprising events they have refrained from commenting for sometimes quite a long time. The fact that they congratulate Lukashenka so quickly suggests that they were able to get a rapid confirmation from officials that this should be promoted instead of condemned, and it suggests that more likely than not this wasn't a surprise for Kremlin, that they were informed beforehand or perhaps even participated in making that "brilliant special operation" happen.