Heathrow Airport takes an innovative approach to categorising short- vs long-haul - see
Fly Quiet League table Q4 2018.
Note that in 23rd and 39th position, respectively, are "Turkish Airlines - long haul" and "Turkish Airlines - short haul".
This is despite the fact that Turkish only serves one destination - Istanbul - to/from Heathrow.
Digging into Heathrow's
methodology reveals that aircraft under 180 tonnes (effectively all narrow-body types) are classed as "short haul" and those of 180 tonnes and over (i.e. wide-bodies) are classed as "long haul".
On second thoughts, that probably doesn't help you very much.
