Your iPhone last reported location will be available for 24 hours in the Find My App on an iPhone, iPad or Mac, or icloud.com/find
If you log on to Find My, does the phone's location appear near the Frankfort airport on the map?
This might be a notification that another iPhone or Mac picked up the Bluetooth signal that the iPhone was sending out to update the location on Find My.
You were not asked to log on to another non-Apple site or do anything like that or click a link, were you? In other words, it was simply an informational message, correct?
The scams are always messages asking you to click on a strange link or log on to another strange site and remove your phone from Find My or provide your passcode, and other log on information.
You may be able to see where the phone is located in another day or two if another iPhone picks up the signal from your phone and forwards that location information.
If a phone is stolen, the first thing that the thief will usually do is wrap the phone in aluminum foil to prevent the phone from either sending or receiving a signal.