There are foreigners in the USA doing jobs that Americans don't want to do.

My son was born in the USA, i wasn't. Does that mean i cannot work to support him till all americans in the US have jobs?
What about if i go back to England? Does that mean that he shouldn't be able to work there till all the british have jobs?

I've had my green card for 25 years. When would i qualify to work as an airline pilot in your world?