I've had a brief look at the post-Brexit UK-Norway bilateral - you can find it at -
https://www.gov.uk/government/public...norway-no12021 (see Article 4 on page 6 and Article 14 on pages 16-17)
It seems to say that any airline flying a scheduled service between the UK and Norway has to be established in either the UK or Norway (ownership of the airline can be from anywhere in the UK, EU or EFTA). This would explain why Ryanair flights between the UK and Norway are operated by Ryanair UK, a UK based airline.
A number of flights Heathrow/Manchester and Oslo seem to be listed as "operated by Cityjet" or "operated by SAS Connect" on the SAS website
Does Cityjet have a UK registered airline subsidiary ? If not, why can Cityjet operate a scheduled service between the UK and Norway ? Does the freedom for EU airlines to fly anywhere between the UK and the EU extend to flights between the UK and Norway ? If so, why do Ryanair Ireland need to use their Ryanair UK subsidiary to operate UK-Norway ? Or do Ryanair Ireland have full rights to fly UK-Norway ?
Equally, how does SAS Connect (i.e. the Irish subsidiary) manage to fly between the UK and Norway ?
Is there something to do with leasing (i.e. Article 14 of the bilateral)... in which case could Ryanair UK lease a Ryanair Ireland aircraft to operate UK-Norway ? If Ryanair UK can lease a Ryanair Ireland aircraft to fly STN-OSL, why do Ryanair Group need to use G-registered Ryanair UK aircraft at all on UK-Norway ? I can't see anything in the agreement which talks about "UK/Norwegian airlines at least 50% of the time" - it seems to be a binary all-the-time yes-you-can or no-you-cannot
Was there perhaps some behind-the-scenes political agreement whereby the CAA/DfT refused to designate Ryanair UK as a UK airline under the treaty unless Ryanair Group agreed to establish a substantive UK subsidiary ?
I'm just curious as to why Ryanair Ireland seem unable to fly (and have to use Ryanair UK instead of leasing in Ryanair Ireland aircraft) on STN-OSL, but Cityjet and SAS Connect seem to have the right to fly UK-Norway on behalf of SAS...