KLM do not check ID on the way out of AMS (unless you check bags), but there are ID checks at boarding in Spain.

Even before 2015 there used to be very regular checks on the Cerbere-Portbou train border, I've seen people send back to France for trying to enter Spain without having a proper ID.

Surely, the other way around is even a bigger risk.

I would strongly suggest to the OP not to bet on not being checked at all.

And it doesn't really matter what the Dutch authorities say about the legal rights of a residence permit. It's all about the airline's own regulations - and a written answer from them will definitely help as well for any rogue officer thinking otherwise if checked at an airport.

That is indeed how it generally goes.

A Dutch resident permit for a non-European citizen without a passport or other accepted international travel document won't generally work to fly from Spain to AMS. More often than not, such person will be able to pull it off when flying from AMS to Spain (at least if not checking in luggage).

The US embassy/consulate staff in the Netherlands can issue a secondary, limited duration ordinary US passport. But the best time to pursue such is before submitting a primary ordinary US passport for visa. Getting such while in Spain has been done before.

well, first on the list once I get past this is applying for a second passport. This is a pain! Unless anyone has any recommendations for a document I can get as a US Citizen that will allow me to fly while my passport is stuck at embassies for visas.

I've never tried this, but would a Passport Card work? :D

I'm not talking about the legal side of things, but rather the practical side.

Not likely. A US Passport Card most frequently gets rejected for such trips in my experience of trying it. :D

Nope. A travel document issued by a EU member state should work though.

yep.

spain and italy are sticklers for checking , or , rather, requiring passports for schengen flights.
sometimes ive successfully talked them out of it. sometimes, not.

a visa/residence card is NOT a valid document for travel without the accompanying US passport.

ask me how i know

While it generally is not, sometimes it can be a US citizens' valid document for travel without an accompanying US passport; but then another document beside a US passport would be required.