I have to say that I did have a frustrating time with local tourist organisations, one of which was a taxi transfer from the airport that never materialised, and with a tour company - a different one from the taxi one! - who failed to turn up on the next day for a pre-booked (but thankfully not prepaid!) city tour.

Frankly I'd recommend one of the majors from Thessaloniki airport ... I think we eventually hired for our week's tour with Hertz ... and as the airport is quite a fair way out to the east of the city, it would save you transfer fees as well. Just make sure that your Thessaloniki lodging has a car park ........