Is there any way bitcoin payments could get taken in an aircraft with no net connection for duty free sales or buying food?
I guess the airline could scan the qr code but there may not be any funds associated with that code. I know some airlines now have wifi but not many.
Many airplanes have internet connection and have wifi. In the event that they could not use the internet the process could be as follows:
1 - Download the blockchain immediately prior to takeoff
2 - When a passenger wishes to purchase an item the flight attendant would give the passenger a Bitcoin address to send the BTC to along with the amount to send.
3 - The passenger provides a signed
transaction to the flight attendant. This could be done via wifi and/or bluetooth.
4 - The flight attendant checks to make sure that the outputs provided in the transaction are unspent as of when the blockchain was downloaded (this step would almost certainly be handled by the airlines software, but the flight attendant would cause this check to take place)
5 - The passenger gets their food/drinks (or the duty free items are ordered)
6 - When the plane lands the transaction is broadcast to the network by the airline
The risks involved are very similar to those for accepting a 0/unconfirmed transaction. Although the airline does not have an up-to-date copy of the blockchain, the passenger them-self would not be able to move any BTC around (someone else could if they had access to the private keys).
In the event that the passenger is ordering something duty-free then the airline simply broadcasts the transaction throughout the network when it lands, and the transaction would likely have (close to) 6 confirmations by the time the passenger arrives to pick up the order (the time spent taxing from the runway to the gate and the time it takes for all the passengers to get their luggage out of the overhead bins and exit the plane a lot of time will have passed, allowing plenty of time for the transaction to be sufficiently confirmed).
