Originally Posted by
BenA
This isn't necessarily correct. It is possible: the protocol that hands out IP addresses, called DHCP, can optionally specify the time zone at the same time.
RFC 4833 has the details. So if Delta's router is set to the wrong time zone and a device is automatically using this information, it could cause what OP describes.
Even that RFC suggests that new timezones acquired this way shouldn't be authoritative though, and that a prudent design would be that changes should be confirmed by the user rather than automatic.
OP, what kind of device are you seeing this behavior on?
A chromebook. The device by default will go with a auto configuration time and time zone, but this can be disabled.
Typically I disable any such when traveling just to avoid confusion, but I did not realize I had to worry prior to leaving town :-)