Upvote:5
Most likely not a problem but at least in one case Passenger refused flight over missing letter on airline ticket -- but the title is sensational if you read carefully all the airline said they can't guarantee the connecting airline won't have a problem.
This thread reports a number of cases when this hasn't been a problem.
This forum post says
Turns out I've been flying with different middle names on my [driving licence] and passport for years. Tickets match passport, but I've often showed my DL and no one has batted an eye.
Summary: I would call the airline especially if you are connecting.