Going by a website on my laptop the following distances apply
Glasgow to Dalaman 2035miles
Glasgow to Tenerife 2017miles
Glasgow to Rhodes 2028miles
As you can see the distance is pretty much the same.
Checking the price for the period 19/Sept to 3/Oct cheapest to Tenerife from Glasgow was £160, Out with Thomson back with Thomas Cook Rhodes from Glasgow £154 out and back with Thomas Cook
Dalaman from Glasgow £388 out and back with Jet 2
I think it was Scunner who said the flights to Turkey were subsidized by theTurkish government, if that is indeed the case where is all the money going,not to the holiday makers obviously. I do think there is a bit of a vendetta against Turkey. And as for the difference in price between north and south airports the dearer price cant be justified.