Norwegian registered rather than Irish registered does not change the problem.
Example - Norwegian operating LGW - TFS with state aid in direct competition with EasyJet also operating LGW - TFS without state aid, can’t see the UK government going along with that one, they let Flybe et al go under remember.
Norwegian flying out of Norway with state aid on a Norwegian AOC - not an issue but protectionism in the EU is rife and they will look after themselves
”norwegian air uk is a UK AOC, flying G reg aircraft” eligible for state aid from Norway without breaking competition rules?