Ryan Air or Norwegian Air?

Which London airport do you prefer? That being said, Norwegian is not as bad as Ryanair. Also note that you have to pay extra to use the overhead luggage lockers with both airlines.

From Oslo to London you also have the choice of SAS or British Airways. And from London to Bergen there is also Widerøe. All flying to Heathrow.

No, all airline carry on sizes are NOT the same. Measure from the ground to the top of the handle. Check each airline's carry on policies.

So does anyone have experiences with these two airlines policies in particular and can compare them, including carry-on size? These are best best choices for flight times, according to Google flights, who can handle a multi city search.

Please measure your carry-on size precisely. Low-cost airlines in Europe are super strict--at the gate, they weigh carry-ons and ask passengers to put them in their sizers. Anything that does not fit has to be checked-in for a hefty fee.

RyanAir doesn't fly into Bergen. Norwegian Air Shuttle flies from Gatwick into Bergen--as does Widerøe Airlines into Heathrow.

Norwegian Air Shuttle flies Oslo to Gatwick--as does Scandinavian Airlines. RyanAir flies only Oslo to London Stansted.

I've flown Norwegian Air Shuttle many times, and they're preferred.

Have a great time. We found Bergen to be absolutely lovely with the sweetest, tallest and most beautiful people we've ever experienced.

RyanAir's baggage policy: https://help.ryanair.com/hc/en-gb/articles/360017824658

Norwegian Air's baggage policy: https://www.norwegian.com/uk/travel-info/baggage/hand-baggage/

Note: there are size and weight limits. There's a difference between a personal item (fits under the seat in front of you) and carry on bags which fit in the overhead compartment.

So other than baggage, are these guys pretty much the same?

No, they are not pretty much the same. While they are both pretty bad in my opinion, Ryanair is by far the worst of the two. At least Norwegian offers you such luxuries as allowing you to check in for your flight at the airport for free, Ryanair charges €55 for that privilege. You should also check if the Ryanair flights actually are from Oslo or if they are from Sandefjord.

These are best best choices for flight times, according to Google
flights, who can handle a multi city search.

This sounds like you are making it a lot more complicated than you need to? Why doing it as a multi city search, that seems like it just complicates things. Treat it like two one way trips. And there are as mentioned other options as well.

And where in London are you going? That can make a difference, especially if your final destination isn't actually London.

I flew Norwegian twice prepandemic on an intra-Norway route. The airline was great. I have not flown Ryan Air.

Same here; I have flown Norwegian in Europe and Easy Jet (another successful low cost European based airline) but have been uncomfortable with trying Ryanair just from the bag rules and some of the out of the way airports they fly into. I would go Norwegian

Yeah, we've decided against Ryanair.

Good decision. TBF I've never flown Norwegian Air but vowed many years ago never to fly Ryanair again and have stuck to it.