For those who used to be train spotters when young and happy
British Railways (in the days they used steam kettles to haul things around) used to have a proper crest (known by all and sundry as the "lion on a dartboard") and did the same thing, changing its orientation so that the lion faced forward when looked at from either side.
Someone pointed this out to the school of heralds (or whoever) and they told them it was wrong, any heraldic device only has one way of being displayed and hence British Railways had to change things around.
I would assume flags are also heraldic devices.
(Also, are people who paint the flag on planes as if they were just flags flying from a flagpole just stealth wanna-bes who think their plane is invisible ?)