You might find it useful to know where you can get direct flights to from Glasgow.
Here's a map:
http://www.glasgowairport.com/destination-inspiration/route-map/
(Click 'Europe' in the left-hand panel)
and here's a list:
https://en.wikipedia.org/wiki/Glasgow_Airport#Passenger
There's a destination map for Prestwick Airport here:
http://www.glasgowprestwick.com/
and there's a list here:
https://en.wikipedia.org/wiki/Glasgow_Prestwick_Airport#Passenger
Barcelona would be my choice:
http://www.barcelonaturisme.com/wv3/en/
It certainly meets your requirement for being near to an airport, as Barcelona Airport has its own rail station, which is just 27 minutes away from the central Passeig de Gràcia station. Within the city itself, there's a good, cheap and fully-integrated public transport system.
Barcelona is packed with excellent restaurants and bars, with loads to see and do. It's especially good for kids:
http://www.barcelonaturisme.com/wv3/en/page/93/with-kids.html