Norwegians 15 737-MAX8 are of course still grounded. No airline is "cheating" and flying with a grounded plane.

The planes are very similar (which is the whole selling point). That's why they can use the same safety instructions, which is probably where you saw the text "737-800/737 MAX8" printed. As others said, they are most easily told apart by the different look of their wing tips.

I think it's unlikely that it was a 737-MAX, Norwegian should have just 18 737-MAX and more than 110 737-800. Source: https://media.uk.norwegian.com/pressreleases/update-on-the-t...

EDIT: Lol, nevermind. Go read the child comments. I failed.

There are two features you can look for:

https://aviation.stackexchange.com/questions/48929/is-this-a...

tl;dr on the MAX the wing tips split into two (above and below the main wing), on all previous 737s, the wingtips only curve up. Also the engine cowling has some cool looky jaggies on the trailing edge.

> on the MAX the wing tips split into two (above and below the main wing), on all previous 737s, the wingtips only curve up

However there are aftermarket wingtips for the 737NG (737-600/700/800/900) which are similarly split that a number of major operators have fitted.

I was plane spotting two days ago and saw a half dozen 737NGs with split wingtips.

Boeing also has the model number on a plate in the doorway. Of course if you can read it, you've already boarded.

That winglet design is not specific to the MAX aircraft. That CFM engine is also used on Airbus NEO.

I had not seen the split winglet on non-MAX 737s. I stand corrected. I did mean the CFM engine as a distinguisher between 737 models, not as a identifying feature for 737 MAX vs all other 2 engine smallish jets.