> was supposed to board a plane to Europe yesterday but was denied boarding to due to the fact that my passport expires within 90 days. Not before I return, just within 90 days. I had no clue this was a rule

Oof, and it gets another one. FYI the reason for this is because the agreement between the United States and the country you’re going to (I’m assuming you’re going to a Schengen area nation) silently says you can stay over there for max 90 days. If your passport expires within that period that obviously becomes problematic, so many countries will just deny boarding if that’s the case. This hits a lot of Americans each year, with some being allowed to board, fly across the ocean, and get denied entry at passport control. So at least you were spared that?

Such rules don’t just apply to the Schengen area of Europe either; the situation is similar with Canada. This is one of those major international travel little-known tips that really should be underscored and stressed when you’re applying for a passport and when you get it.

https://travel.state.gov/content/travel/en/international-travel/before-you-go/travelers-with-special-considerations/schengen.html

Anyway, hope you’re able to find a quick solution here.