Solution to #11: As The Crow Flies
Each license plate contains two airport codes, split equally between the United States and Europe. On the license plates referring to American airports, one of the airport codes matches the state of the license plate:
Source City 1 Destination City 2
------ ------- ----------- -------
OAK Oakland SEA Seattle
BFI Seattle DAL Dallas
DFW Dallas MDW Chicago
ORD Chicago PIE Tampa
In this order, the license plates form an unbroken path across the country. Following the same state order for the remaining plates gives a similar unbroken path in Europe:
Source City 1 Destination City 2
------ ---------- ----------- ----------
WMI Warsaw TXL Berlin
SXF Berlin CPH Copenhagen
RKE Copenhagen GSE Gothenburg
GOT Gothenburg OSL Oslo
These paths look like the letters M and L, respectively. As hinted by "as the hours went past", the letter in the earlier time zones (Europe) should be placed first. Looking for a destination with the identifier 'LM' yields Lash Miller Chemical Laboratories, one of the buildings on the University of Toronto campus.
LASH MILLER