I have two flights in 1995 for both of which the calculated time is by one hour two long. I reckon this is *not* due to the shifting of the end of the daylight saving in Europe in 1996 from September to the end of October (same as US), since this effect would cancel out in the sum. In contrast, both flight times are too long, suggesting that one of the two airport is assigned to the wrong time zone (at least in 1995).
The particular flights are:
21.10.1995, 12:20 UTC+0100 - 17:20 UTC-0500, FRA-DFW (summer time in DFW, winter in FRA)
02.11.1995, 14:50 UTC-0600 - 07:35+1 UTC+0100, DFW-FRA (both winter time)
The calculated times are 12:00 hrs for FRA-DFW and 10:45 for DFW-FRA, however they should be 11:00 hrs and 9:45 hrs, respectively.
My calculation is according to www.timeanddate.com and the DateTime-Modul from Perl.