Drive4it:
I think that unless Olympic Holidays are prepared to tell you the name of the carrier that will be operating your holiday flight, and proffer a flight number, I would ditch them in favour of a larger, more professional outfit that can. Would you trust your 2 weeks in the sun to any of the carriers listed as potential operators by sam1993?
The big boys of the industry are probably more likely to: a) get you away on time/day and b) look after you properly if something does go awry.
Until passengers vote with their feet, tour operators like Olympic may never learn the value of customer service.