"Engines stalling" is not really the factor that limits altitude. The problem is that the thinner the air, the faster you have to go to stay up. Eventually the

"Engines stalling" is not really the factor that limits altitude. The problem is that the thinner the air, the faster you have to go to stay up. Eventually the required speed enters the transsonic region, and you start needing way more power. There comes a point where your engines just don't have the oomph to push you fast enough to stay up. If you want to go higher, there are basically two ways - more oomph, and better wing loading (i.e. less weight or bigger wings.) Electric aviation has many merits, but being a lightweight source of plentiful oomph is not currently among them.