Unfortunately this is a prime example of Covid paperwork madness. You can't check in without the PLF (passenger locator form) and you can't file the PLF without having a seat, so you have to check in first.
If you can't get a seat online upfront, you have a bunch of options
- Fudge the seat number. I don't think anyone checks this (but I can't guarantee it)
- Check in at the airport, get a seat assignment, and then file the PLF at the airport. You may have to go to the counter or gate twice: once to get the seat, and again to have your boarding pass stamped with the PLF confirmation. Make sure you have all information handy that you need for the PLF. It asks for an address in Portugal. If you are transiting, you may be able to skip this or just use the airport. Zip code for Lisboa airport is 1700-111 (don't know about Porto).
We flew to Portugal about 3 weeks ago and check in was a disaster. Huge line at the check-in counter moving extremely slowly and another huge line at the gate for document verification (for those people who managed to check in online). As a result the flight left over an hour late.
TIP: the PFL confirmation you get by e-mail is password protected PDF, but they don't tell you what the password is. Turns out, it's your passport number. It's incredibly inconvenient to have to pull out your passport and type in the number every time someone wants to see the PFL. You can remove the password simply by printing it into a new PDF file.
The whole experience was a total mess.
