Ever flown with a free checked bag you didn't use while the person at the counter next to you grimaced at a $60 bag fee? It feels like money left on the table — and a new academic paper agrees. Published in the Review of Economic Design, it proposes a marketplace where passengers could trade checked-baggage weight rights above a baseline allowance, letting people who need extra capacity buy it from those who don't.
The idea sounds neat. You'd recoup value from a perk you weren't using; another traveller would pay less than the airline's fee. In theory, trading directs finite hold space to whoever values it most. In practice, say the skeptics, it falls apart — and the reasons matter to anyone who books flights.
First, breakage. Airlines price tickets, elite perks and credit card benefits on the assumption that plenty of people won't check bags. In a cabin of 100 passengers entitled to a free bag each, maybe 60 actually do. That gap isn't waste — it's option value, baked into what you already pay. Make every unused allowance sellable and suddenly far more bags get checked. That means more handling, more fuel, and a perk the airline can no longer afford to hand out so freely. Expect fewer free allowances, higher fares, or both.
Second, the physics and the revenue don't line up neatly. If the buyer was already planning to check that suitcase, no new bag is added — the airline just loses fee revenue and you pocket the difference. If the cheap allowance tempts someone to bring an extra case, that's genuine extra weight, handling and fuel, and on a tight flight it can crowd out cargo. If they move a carry-on into the hold, the plane barely gets heavier but overhead bin fights ease up. So the costs vary wildly, and airlines can't model a tradable system the way they model today's fees.
Third, security and logistics. Any real version would have to run through the airline, with the buyer checking a bag under their own name. The fantasy of strangers paying you to slap your luggage tag on their suitcase isn't going to survive the first 'did you pack this yourself?' conversation.
Airlines do already permit a sliver of flexibility: Ryanair lets passengers on the same booking pool checked baggage — two travellers with 20kg each can split it 15 and 25, within per-bag limits. That makes a purchased allowance more useful without creating a secondary market.
So what's the takeaway for travellers? If you hold an airline credit card or status that includes a free checked bag, its value lies partly in you not using it — the same breakage that keeps the perk alive. Don't expect airlines to let you cash it in. The smarter move is the old-fashioned one: match your fare bundle and card perks to how you actually pack, and if you fly bag-free anyway, prioritise the perks you will use, like lounge access or priority boarding.
View from the Wing
