IOM-LTN is a completely pointless route for BA/TH to be operating. Seems to be operated simply for nostalgia from the Brymon era. Sooner we're shut of that of airport, the better.
Get real! No airline in this day and age operates a route for nostalgia, if the route makes money it will continue.
The load factors on this route are regularly over 90% and when Manx Airlines operates this route is was only operated 4-5 times a week with a mix on ATP's and BAe146's. Since BA CitiExpress took over the airline they have increased the frequency to daily and flying BAe146's/Avro's on all flights.
I think both airlines can operate side by side, for example Manchester/Liverpool has over 10 flights a day in each direction with different airlines operating the routes.
This competition is urgently needed as BA have dominated the IOM-London market for a number of years.