Apparently the UK is the only G8 country without a dedicated plane for its PM. The No. 32 Squadron performs many flights for Blair and the Royal Family and others are charter flights. I've never heard that he would actually fly commercial. Maybe it was a private trip so he didn't want to waste money?
It seems like a dangerous security issue to me. The UK is one of the countries with a nuclear bullseye on it so the PM should have a dedicated aircraft just for defense purposes. Blair has requested a plane for this reason but the media mocked him calling his requested plane "Blair Force One."
Personally as he was going on holiday I do not think he should commandeer a plane or use the Queen's flight I know there are security issues but to travel commerical I think for a holiday is correct. Why should I as a British tax payer pay for him to charter a plane for a holiday if he paid fine but I do not see that happening.