The only scheduled operators on that route are as follows:
Thomson:
Only one flight on Tuesdays (TOM1289 at 1910) but that's apparently fully booked on 4th January as no availability is shown.
Thomas Cook:
No flights on 4th January.
Jet2:
Flights don't commence until January.
So there simply aren't any flights when you want them. Source:
http://www.glasgowair...nations+and+airlines/
The only flights to Prestwick are with Ryanair. Their website is currently showing just one seat left at €226.39 on the 1845 departure, with additional seats available at €266.39
Ryanair can also fly you to Edinburgh, with one seat left on their 1205 departure at €186.39 and additional seats at €266.39. (The only other operator from Tenerife South to Edinburgh is Thomson, but they have no availability on that date).
Chris