Incognito mode simply deletes any history and cookies stored in a given session. Your browser and device information can still be queried.

Check here: https://www.deviceinfo.me/

You’re right- theory probably wasn’t the best word. It is known that companies do this but it’s impossible to concretely say how and in what circumstances prices change.

There is a theory that travel websites use trackers and other information readily available about your device and browser to advertise different prices to different people. A lot of VPN companies use this in their marketing actually— showing different prices for the same airline tickets depending on which VPN server you’re connected to in the world.

I haven’t done much research on this personally, but you may be able to see it in action by opening the same site in a normal and an incognito window and searching for a flight/hotel. Or trying the aforementioned VPN trick. There however doesn’t seem to be any specific rhyme or reason for it, and no one can say that XYZ browser connected to ABC server will get you the cheapest prices. There are just way too many variables in play and these kinds of algorithms the websites use are all well-guarded secrets.