Airlines do issue their own passes, albeit only two in the UK BA and easyJet.
All that is required for an airside pass is a Basic Disclosure certificate with no offences that render you unable to gain an airside pass.
Click Here for the disqualifiying ones. On there is not DUI, as someone previously stated in the post.
You can now, by law, say 'I have never been convicted of an offence', and again as others state, certain professions demand you and can request your full history.
At present Airlines do not insist on your spent history for this.
In short you are home and dry mate, despite what these guys say and if any recuirter says he wants to know if you have ever regardless of an offence being spent been done for DUI then that is in breach of your rights.
My brother had the same concern when he joined a major corp. (non-flying) and they wanted to put him on the pool car insurance. After much musing he just told them and they said it was in confidence, and they have several people on there with the same. In short, plenty in the same boat mate!
We can all get excited about this subject as it is one quite close to a lot of our hearts at the moment, with all the breathalising going on airside, but the long of the short of it is, you did the crime, you've done the time now get on with getting a job and dont listen to some people on here who love to get excited about how great they are and you arent.