I thought most POS devices stop accepting "offline" payments.
I definitely remember making an _offline_ payment with an AMEX card at a restaurant in the UK some 10 years ago.
Also, most airlines that take payments on board also run the terminals in offline mode.
There must be some mapping of BIN codes and whether to allow an offline transaction.
The way the rules are set up though, the risk of a failed offline transaction is almost entirely borne by the merchant. In most cases the merchant is unwilling to accept this risk and disables the feature.
I don’t typically carry any cash on me, and, well, if their terminals go down before I’ve closed my tab, they assume all of the risk anyway.
they would pass the card with one of those old engraving things lol
Transactions with the cards requiring authorization will take several seconds while with my other cards it will be instant most of the time.
It depends on the configuration of the terminal : most merchant will allow offline (or asynchronous) transactions up to a certain amount when there is an important flux of customers waiting to pay.
I’m also pretty sure (that’s speculation at that point but I felt it in my experience) that some cards have more chances to have instant (offline) transactions than others. The more « premium » the cards the less I saw the "waiting for authorization" screen. Especially for small amounts.
Anecdotal, but most airliners I have recently flown with seem to have switched to online POS terminals, though they do still seem retain offline payment functionality as a fallback. I've seen payments being made, only for the flight attendant to return back to the passenger a few minutes later to inform that the payment was declined. This was over the ocean, so definitely no ground communication.
Airplanes for commercial flight all have VHF/HF or satellite connectivity, the've had that for a long time already. It's used for functionality like ACARS, voice connectivity, remote monitoring / diagnosis, etc. I can imagine this can also be used for payments and other low-bandwidth functionality.
Most airplanes also have WiFi access points on board, even when not offered to passengers. Typically these use hidden SSIDs. Speaking to an airplane tech once I know these are used for flight-crew handheld devices such as the POS terminals and iPads.
I happen to have a few friends that are pilots (all working for the same company) and they told me that their entire fleet already has Starlink terminals retrofitted, though they aren't offering that to passengers yet.
I guess what I'm trying to convey here is: the era of airplanes being 'offline' is already behind us.