Its Got To Mean Something...
 

A truly odd piece of data emanating from WWII about aces was the fact that two thirds of them turned out to have -

1. Blue Eyes

2. Were Shorter Than Average

3. And Later In Life Had More Daughters Than Sons

This may someday turn out to mean something, but to this point in time no one has figured out what it is.

I understand that jet fighter pilots in the modern era have only daughters.

Shorter then normal?
 

That is easy to explain, have you ever seen the inside of a fighter cockpit...ie. the ME109. I don't think a big handsome guy like me at 280lbs and 6'4" would last long. The eye colour has me scatching my head. the having girl thing is also easy. It's like truckers that also have on average sire more girls then boys. If you sit for long periods of time, you warm up the boys and this kills the male sperm allowing the female sperm to fertilize the ...... I hope I don't have to go into the whole reproductive thing here.

100% of Mexican Aces had brown eyes. Wait... there weren't any Mexican aces!

Nice try Mark but i doubt there were any blue eyed Japanese aces running around either.

Your theory does hold some merit 2054172, as far as German machines go, but even i could fit inside most American fighter cockpits of WWII. I should know, i have sat in a few of them.