We just returned from a trip to Sweden. Here is what we experienced with regard to testing and paperwork requirements.
We flew Delta airlines and their European partner, KLM.
Itinerary was Pasco, WA - Salt Lake City - Amsterdam - Stockholm Arlanda airport.
Return trip: Stockholm Arlanda airport, Amsterdam, Seattle, Pasco.
First question: Do we need the Amsterdam and Stockholm testing/paperwork prior to leaving Pasco. For non-EU citizens, Sweden requires a negative Covid test no older than 48 hours old upon arrival in Sweden. From Pasco this is an impossible time line. We tried to find out if we would be allowed to board our flight in Pasco without the negative test or if we could test during a layover. Never did find the answer to that SO we erred on the side of caution and got an RT-PCR test in Pasco the day before our flight. Results of this would be too old upon arrival in Sweden but would get us to SLC. Prior to leaving, I found a testing center located in the SLC airport, post-security, and made an appointment for testing during our layover for the connecting flight. RT-PCR test had a 2 hour turnaround time, cost $250 each and included the required medical certificate with all information required by Sweden.
Entry into the Netherlands requires proof of vaccine and the Netherlands Health Declaration, available at Delta's website.
Leaving Pasco only our passport was checked so that answered whether or not you need your international destination paperwork if you have a connection within the US. Could have saved the cost of the first RT-PCR test.
Delta SLC to Amsterdam flight: Our passport and Netherlands Health Declaration needed for boarding. Gate agents required a paper copy of the Health Declaration. They had them available at the gate for people without a paper copy. No one looked at the vaccine card or negative Covid test result.
Amsterdam arrival: Passport control absolutely packed. Literally hundreds and hundreds of people in line to get through passport control. Masks are required but it took 1.5 hours to get through the line. At this point only the passport was looked at. Be ready for long lines and lots of people. Also, be sure to have a EU plug adapter with you as there were no USB plug-ins available on the chairs in the airport.
KLM Amsterdam to Stockholm flight: Only our boarding pass was checked at the gate. Passport, health declaration, vaccine card, negative test not looked at to board the plane.
Arrival in Stockholm: Even though we entered the Schengen area via Amsterdam we had to go through passport control in Stockholm too. This is where all paperwork was checked. Our passport, CDC vaccine card, negative Covid test result were all thoroughly examined. The testing time and date were highlighted by the passport control agent.
Return trip:
KLM Stockholm to Amsterdam flight: The US requires negative Covid test taken within 3 days prior to arrival home, regardless of vaccination status. We Covid tested at Stockholm's Arlanda airport the day before our flight. There are 4 testing facilities inside Sky City at the airport. Our RT-PCR results were back in 6 hours via email. We asked hotel front desk to print our negative result/medical certificate. You will need the test result on paper not just digitally.
Big surprise was KLM and Delta did not allow online check-in for this flight because they needed to physically see the negative test result. Could not check in via the KLM kiosks either and no baggage drop available. We had to stand in line and be checked-in at the counter. Get there early! 3 hours ahead is not too early.
At the gate: passport & boarding pass needed.
Delta Amsterdam to Seattle flight:
At gate: Passport & US Health Declaration required. The gate agent collected a paper copy of the Declaration, available at gate. Proof of vaccine, negative test result not looked at. Good luck and have a fun trip!