[T. Rustin Noone]

I imagine landings would be a real challenge for the returning aircraft.

[Steely Tom]

They landed at the base on regular runways. The aircraft were lowered to the underground catapult using elevators.

Probably a massive clone of the technology they developed for aircraft carriers, adapted for use underground.

The interesting thing is it was probably never capable of militarily significant usage in time of war. It was (I believe) more of a demonstration project, to wow the suits back in Moscow and show them how invincible the Mighty USSR Air Forces were. Whether it was actually useful was of secondary importance.

Kind of like the ekranoplan. Some big-shot's pet project back in the 1970s.