I travelled from FRA to ATH on 31/8. This flight all in all was quite good, particularly as the plane was 2/3 full there was plenty of space. Flights attendants were attentive and professional. However disaster struck on the return leg on 11/9. I selected my seat on-line the day before travel. Having flown on a 737-400 outward I was surprised to see a 3-2 seat configuration on the return. I selected row 24 (designated emergency on the plan) as being in a 2 seat section. I reconfirmed this selection at the check-in desk at the airport where I was informed that the flight would be operated by Sky Wings Airlines and not Olympic. We were bussed to a tatty ancient MD 83 where the cabin was full of peeling off sticky tape and greek labels covering over the original spanish ones. The seats and carpets were grimy. Then the real problem - the configuration 3-2 was inversed compared to the plan and the emergency exit supposedly in row 24 was in fact in rows 22 and 23. The seating is extremely cramped on this charter-style aircraft. Furthermore I question the reliability of the seats to protect in accident - the seatback stopped at the level of my neck thus making whiplash injuries inventible. Flight attendants, although pleasant seemed inefficient making constant returns between the trolley and galley during meal service. I was served my breakfast, but my adjacent passenger had to wait over 10 minutes longer before receiving his. Breakfast consisted of rubberized omelette, frankfurter and 3 canned mushrooms, plus a chocolate cup-cake. The flight arrived in Frankfurt 40 minutes late after what was supposedly an ATC delay. I was thankful to get off this miserable flight. If I book Olympic I expect to fly Olympic and not a fourth rate charter airline. Next time I'll take Aegean or EasyJet - just to make sure I won't end up on Sky Wings.