Made it back from Spain/Portugal with no issues (and no Covid!). Spain had no testing requirement to enter if fully vaxxed so that part was easy. There is a travel form that you have to fill out online listing vaccine details and it gave you a QR code to be scanned on entry but it seemed inconsistent as they only checked mine, not my hubby’s. To go from Spain to Portugal by air, testing was required (because of the fact there is no reciprocal agreement with US/ Portugal on our vax records). We used the proctored eMed test in our hotel room on a wifi call and it was super easy. Basically you scan the QR code on the box to start the test (after making an account), they watch you do it and 15 min later they rejoin and confirm the results. They send you an email and a QR code. We uploaded the result into the Air Europa app for that flight but no one actually asked to see anything at the airport. For the flight from Portugal to US, we did the same eMed proctored tests and tried to upload the info to Delta FlyReady but nothing would upload. From what I understand that app is very buggy for the Covid test part. But when we got to Lisbon Airport, we just showed a Delta rep while we were checking our bags and that was that. Very easy!