here's an idea out of left field, to help fill seats

[odysseus]

Don't think interest free has been used much in travel, just mainly in electrical goods, which are perishable (new models just around the corner) but nothing like the perishability of airline seats.

There's a reason. Travel is a much riskier "asset" - as it's not an asset.

If you don't pay 3 years after you get the fridge, they can just lay claim back on the fridge - and it will still have ~50% of value.

If you don't pay 3 years after your flight, what asset can be claimed?