You were going to spend $900 on a seat at the back. On that route, on that date, the flat bed is $1,400. Nobody told you, so you booked the $900.
flyingfine is a ChatGPT plugin that runs the comparison you would have run yourself, if flight search made it easy. Cheapest economy, cheapest business, and the gap between them.
Example
New York to London, mid-November.
$852 more for a flat bed, nonstop, and an hour and a half quicker. That is a 2.0× multiple where 3.4× is normal for a route this length.
Why the gap moves
The business-class premium is not a fixed markup. It runs around 2× economy on short hops, 3.4× on long-haul, 4× on the very longest routes — but any particular route can sit far from its norm.
Competition does most of the work. A route with four carriers flying flat beds prices differently from a monopoly route, and the premium cabin is where that fight shows up first, because that is where the margin is.
Direction matters too. A route thick with corporate travellers outbound on Monday can be soft coming back, and business swings further than economy does.
And seasonality hits the cabins unevenly. In peak leisure weeks economy fills and climbs toward business, compressing the gap even though nothing about the business fare changed.
So in any given week there are routes where the flat bed costs barely more than a middle seat. Cheapest-first sorting buries them on page nine. That is what this is for.
What it will not do
It does not sell tickets. No checkout, no card details. When there is a fare worth having, you go to the airline and buy it there.
Prices are indicative and should be confirmed before you commit. When business-class data is not available for a route, it says so rather than inventing a number.
Cost
Free. A booking link may earn a commission from the airline or its booking partner. That never changes your price, and it does not influence what gets shown — the tool reports the cheapest fare it finds in each cabin either way.
Status
In development. Not yet available in ChatGPT.
Contact
Not affiliated with any airline.