Upvote:3
I was unable to find a picture, but my understanding is that Åland passports are functionally identical to Finnish passports in every way except the extra "Åland" label on the cover. This includes using standard Finnish country codes inside. Per the Finnish police, which issues all Finnish passports:
Jos hakijalla on Ahvenanmaan kotiseutuoikeus, hänelle myönnetään Ahvenanmaan passi, jonka kannessa on lisäteksti Åland.
https://www.poliisi.fi/passi/lisatietoa_passin_hakemisesta#Lis%C3%A4tietoa%20passityypeist%C3%A4
Loose translation:
"If the applicant has right of domicile (kotiseutuoikeus) in Åland they will be granted an Åland passport, whose cover has the additional text Åland."
In general, while there are residents of Åland and the islands have a great deal of internal autonomy, they are still citizens of Finland and treated as such for all international affairs -- including passports used for travel overseas.