Translation of erwachsen

A bystander who watched the entire scene all the time decided to help me. He was an older man, around seventy, but nonetheless he went to the oldest of these kids and slapped him. The boy was sixteen.
Every school has some narrow minded teachers who are not willing in investing in progressive educational process. They do not grasp that schooling methods today are different from last century's methods.
The same day that I gave my last presentation about our pilot project I flew away. The first lag was NYC's airport John F. Kennedy. I left Europe after midnight and arrived there at five o'clock, more or less.