Firstly, there are currently no direct flights from any Scottish Airports to Lisbon.
There are direct flights, however, from Edinburgh, Glasgow, Glasgow - Prestwick, and sometimes Aberdeen to Faro Airport in the Algarve.
You should be aware that rail links between Portugal and Spain are difficult as are low-costs flights between the Algarve and Spain.
There are good rail links between the Algarve and Lisbon.
You should plan therefore on using long distance coaches.
Have a look at this recent article on my blog.
http://barlaventostravelblog.blogspot.com/2009/01/lisbon-to-algarve.html
In summary, I think that a routing as follows might be appropriate:
Scotland to Faro Airport.
Faro Airport to Lagos - Private Transfer or Bus/Bus or Bus/Train
Lagos to Seville - 2 x Daily Bus
(See: http://barlaventostravelblog.blogspot.com/2008/12/granada-seville-lagos-madrid.html) and (http://thomasallen.home.sapo.pt/travel/001.htm)
Seville to Madrid - High Speed AVE train. (See: www.renfe.es)
Madrid to Lisbon - Long Distance bus (See. www.alsa.es) or Low - Cost Airline (vueling.com or easyjet.com)
As regards other places in the Algarve, consider Tavira.
Hope this helps.
