Towing

I only thought sailplanes did that...could be to save on gas?

Hmm, could be - but it also might be to get aircraft out of the terminal position. Eg, on busy days, the aircraft doesn't have that much room to roll left and right while leaving the gate area. I don't mean the tow trucks take them out to the runway, just out of the gate area.

Eg. Why is this KLM towed into the gate, whereas it is, as far as I know pefrectly capable of doing that on it's own ➡

http://www.airliners.net/open.file/728990/M/

I would think they are concerned with the jet exhaust in close proximity of other aircraft or buildings. Therefore it is safer to tow them out past the apron and let them depart from there.

Simple really....either been in maintainance or going to....change of stand etc etc