Here are some additional quotes from airlines which are contained in the competition commisioner's working papers that GoEDI referred to
(http://www.competition-commission.or...ing_papers.htm);
Like Emirates, Thomson does not believe that EDI could handle additional international traffic. They said;
EDI is also very full with domestic traffic and so Thomsonfly traditionally operates from GLA. The only sensible substitute for GLA is PIK but this is not something Thomsonfly has ever investigated seriously.
EDI is currently constrained by domestic traffic but we do use crew based at NCL to operate our EDI flights .......
As mentioned previously EDI does take some of the traffic from NCL in the overlap in the difference between the British and the Scottish school terms.
TNT did not consider GLA to be an alternative to EDI but said;
We do use Prestwick for operational diversions but would not wish to on a permanent basis - it is not best placed for our business. Having said that, if charges in EDI became uneconomic then we would have to rethink our position.
Delta said;
To a lesser extent [than LHR is substitute for LGW], Glasgow International (GLA) could be considered as a substitute for EDI for Delta’s service to Scotland, although Delta’s preference is to offer this service through EDI.
There are no comments from Continental in the competition commissioner's working papers, but the fact that they choose to operate twice daily 757s to Newark rather than a daily widebody perhaps indicates that they don't believe that EDI can handle international widebody traffic?