[iamben]

Not sure how I feel about this. It annoyed my greatly on my last RyanAir flight that in order to take a slightly larger than laptop sized bag (35L) I had to pay for priority which was 8 quid or whatever. A Primera flight I've just booked is now doing exactly the same. Small bag free, bigger bag not so. But, as some of the comments here, I think it sped things up once on the plane. However, adding the extra charge leaves a bitter taste in my mouth - "here's the price for you cheap flight, but here's the actual 20% more price now you have to add a bag". It'll be a smooth win for the first aggregator (Skyscanner or whoever) that adds a 'taking max size cabin bag' option to their search and includes it in the price.

[doctorOb]

I'd say this is an open problem in the metasearch space right now. Airlines are increasingly splitting out what you do and don't get with your ticket into different fare classes, which they brand and line item themselves, making it difficult for a typical traveler to make heads or tails of whether they do or do not get a cabin bag or complimentary meal, etc.

[bumholio]

Google flights already has an "access to the overhead bins" tick box, but yes, there is space to improve the comparison.