Most flights from GLA are B737-800. Seats don't recline , seat pitch is generous (not sure of the exact pitch) due to the clever seat design. The interiors of all the aircraft are very new, they have been refitted and had larger overhead lockers fitted to help with room in the cabin.
Enjoy your trip.
Great news about the non reclining seats and seat pitch, fed up having my knees round my chin, can't wait to get time off and let someone else do the driving