a plane using hydrogen wouldn't make it any less safe if anything it could be safer in general since hydrogen is less toxic and less hazardous than jet fuel, Hydrogen plane would be a good thing, not like THE solution to climate change but good.
also air travel is basically the only thing in the capitalist world that has adequate regulation, unsafe passenger planes would not make it to a runway.
Just about all people who migrate from socialist countries to capitalist one do so for economic reasons not ideological ones, this is self evident in that its very rare for one to migrate to a capitalist global south country.
All (successful) revolution so far have happened in global south/backwards/periphery countries so in many cases while socialism raised living standard of all working people, its still better to live in the imperial core for some people, so reality is that in cases like Cuba and Venezuela they arent fleeing communism they are fleeing the legacy of colonialism or they are fleeing the sanctions imposed on socialist countries (which is an attempt to re establish a colonial relation so kinda the same). Or in the case of the no longer existing socialist countries in eastern Europe its a little different people were fleeing lesser development rather than colonialism. And in both cases they were participating in brain drain which is also a pretty big driver.