As a user, I don't want to be second-guessed. I can explore price ranges on my own, thanks.
It’s all about trade offs and checkboxes(layovers, specific terminals, airlines, aircraft body types, price ranges, dates, non-stops, insurance, in-flight Wi-Fi, meals, early boarding) etc.
Do you first look through the page with all the options, then open different tabs with each unique combination of checkboxes and options enabled/disabled? That must exponentially (literally) harder than simply viewing fuzzy results on screen and pruning the decision tree in your head.
I input my source and destination and date and travel class and then choose from the listed results. At no point I would expect the website to show me business class if I chose economy. If I chose non-stop, I expect non-stop flights and nothing else.
You could offer me a flexible search option, as some sites do (+/- x days on flight times, etc.). Great! Now I can request that we search within a date range. Nice! That might be a good feature for some people!
Offering a simple query interface that returns what it says it will doesn't mean we can't offer flexible search parameters.
Flights are a terrible example of where I'd want to offer fuzzed results... having booked flights on the wrong day before, the last thing I want is to ask for X, but get offered Y.
Logically, you should want to control each of these variables while searching for flights. If you are ready to trust a flight aggregator with these choices, some fuzziness in price seems acceptable too.
You are probably thinking that you don’t want to make a choice about aircraft type or seating configuration and so, whatever the search engine shows in whatever order is fine by you. If so, consider that others might have the same ambivalence towards price fuzziness.
I.e. the UI needs to be there to efficiently help the user do what they ask not to try to be smarter than the user. Unless the user asks for fuzzy matches it doesn't make sense to make the response lead with them.