Climbing to 29 km altitude, the highest possible currently (unless using user-made content), in Simulator mode, flying the new Su-7 plane. The final climb starts about 18:18 mark. After the plane goes above standard altitude limit of 25.5 km and gets respawned, with fuel tank empty, i then glide for 20+ minutes and safely land at the map's central runway.

The last (barely) visible altitude reading during this vertical is 28994 meters when doing per-frame check of this video. Each frame adds ~10 meters at that point, so very next frame (which is still before the plane gets respawned) gets over 29000 meters. In practice, i was doing up to couple hundreds meters higher, even, but that requires taking extra risk going 2.21 Mach before starting the vertical - sometimes the plane endures, sometimes it rips apart.

WT sounds muted because i am enjoying my music during this kind of flying and there is no practical need to hear WT sounds.

As can be seen, the plane is still going some 1100+ km/h when at ~29 km altitude, means that it'll go much, much above 30 km altitude if not the Gaijin's altitude limit. I wish they'd increase it to some 40 km - which we know is possible, because that's how high some planes can vertically climb in user-modded maps before the game respawns them back down to 25 km. And when doing it - there is no crash, no flickering, nothing bad at all. I.e. the game's engine can easily handle up to 40 km, it's a tested fact. So, i am at a loss why this artifucual altitude limit of 25.5 km is kept in place. Other fly sims don't have one. At least, not one under 40 km altitude.

With Gaijin's plans to introduce more and more modern jet fighters, and in particular Su family fighters which are well known for their excellent high altitude capabilities, this altitude limit of ~25.5 km will cause more and more disappointment for more and more players. Hopefully it will be removed soon, and we'll then learn how high one really can go.