Regarding English, there are a lot of Koreans with very good English ability, as mentioned above regarding the cabin crew - some of whom have been my students over the years. What must be remembered is that English ability, or at least English test scores, are one of the key factors required by Samsung, LG and the other big companies for hiring. For the average Korean, aiming for an office job at Samsung will bring more money and be more socially acceptable to parents than the 'dream' of being a pilot. Basically, the system is structured so that those with good English get accepted into jobs that do not need it, and if a pilot has good English that is more luck than anything else as those with good English are working for Samsung. Remember that in Korea, most companies like Samsung will not hire any male who is even one year older than his university cohort as he is then 'too old' and with respect to Confucian values and creates a situation in which a newer employee has more power due to age than employees who have worked there longer.
As for cabin crew, being female it is less of a concern as they do not expect to work much after marriage, hence are more 'willing' to work in a dead end job with good pay for a few years until they get to the verge of the too late to marry / too old to work in the cabin (all by Korean standards). Yes it is dead end because women are often expected and want to quit work when they get married.
There are a lot more dynamics going on here than many realize.