You`re asking the guy that KNOWS nuttin``?! Don`t know, but seems to me they could do a batch run of transactions upon landing (it`s not like people will be charging hundreds of dollars in flight, so risk of insufficient funds would be minimal). Also, I have the impression that even the installed version with card reader may be handled via batch run upon landing (cuts out a lot of connectivity concerns while in flight; i.e., if they had some sort of connectivity out of the plane, and that connectivity was inactive for some reason for any period of flight time, no transactions could be executed - no digE use).

SGE