I think lots of us 'second career' guys and gals are a touch worried about age (I know I am!) but the feedback I've had from OATS, BA, etc tends to suggest it won't be too much of a problem until mid-40s. As far as BA is concerned, the main problem regarding age is the amount of time you have to reach senior positions (eg long haul capt) before they retire you! Provided you don't mind having people younger than you significantly more senior (and some people do), it shouldn't be too much of a worry though. I'm certainly convinced enough to sell my soul to HSBC for a chance at a heavy jet career!