It is a website. With forms. And logic to query a database. And do math.

Aggregators are capable of asking what city, date and time, how many bodies, which service class, which seat, etc. and returning your menu of options with prices based on those details.

Yet asking "how many bags" and multiplying that by the airline's rate is impossible?

Of course it requires changes. I suspect those happen now and then.

My point is that airlines would be able to find something else to withhold by default and charge for if you tried to mandate bag fees be displayed up front. A fee for being allowed to recline. A fee for getting to sit behind someone who isn't allowed to recline. The list goes on and on.

However, then you can't argue anymore that "the market" will handle it. Because even the theory behind that requires that market participants are informed - which they evidently aren't.

That's not how it works. You're creating your own definition of what a market is or should be or how it works.

A suitcase when you travel is not an extra. The payment of the waiter when I dine out is not an extra.

And transparency is not about informing the customer about charges in the fine-print of a website or a menu card. Transparency is being up-front with the total cost so you make it easy for the customer to make an informed choice.

I usually travel with a single carry-on bag when I travel. It's a tiny hard sided suitcase that fits in the carry-on space and includes enough clothes for a week. I don't technically need a free checked bag nor would I typically use one as I want to avoid the insane wait at the luggage claim. So this I disagree with. I don't mind charging for checked bags, but then I don't mind paying more for air travel for certain things, so I don't think that this particular example fits.

I wholeheartedly agree that tipping should go away. It's literally a remnant of the post slavery age in America and has a nasty habit of lowering workers wages. Another problem is taking dine and dash bills out of the waiters wages. The waiter shouldn't be paying for deadbeats.

So I agree with your general point, just not on the airline baggage example.

Require companies that sell online to offer an open API so it's easy to aggregate? Sounds nuts, but not that different from open banking (PSD2) in the EU.

Ok... what information is required in the API? You can't possibly describe every possible differentiating characteristic of a product in an API... even for a specific case like airlines, there are countless differences. Plane type, baggage limits, weight limits on bags, leg room, in flight entertainment, Internet, food, drinks, etc. you want the law spelling out what needs to be included? What about other industries? New ones that are being created? What happens when new features are added that aren't in the api spec? Internet wasn't a thing on airplanes 10 years ago, so it wouldn't have made it in the spec, but now internet access is a huge differentiator for flights.

This is actually an easy problem to solve: define a list of extras in the standard including fees. The structure for each extra can be pretty rigid. Something like e.g.

short-name: Tray fee

long-name: You get a foldable tray for seat to use during the flight.

price: 39,99

includes-tax: false

This is basic data modeling, really. Tne real thing would probably have closer to 50 well defined fields instead of 4 because of real-world self-inflicted complexity in the system, but the concept is the same.

"Pricing transparency laws only help things like "you have to include all taxes and fees for the exact item you are selling"

That is part of the point. You can also have standard prices to quote: "All fees they charge every customer plus one checked bag should be included in price", for example. Airlines that offer bonuses for free will advertise it clearly. After all, we know when a shampoo bottle includes 20% extra shampoo temporarily - I'm not sure this will be an issue. People know that 2 hotels might be the same price but only one of them offers use of a pool - I'm pretty sure they will look at airlines as well.