Don't use "Mr" either. Titles are not required by any IATA protocol and when tickets are reissued can easily cause problems, particularly overseas and particularly when the staff are not necessarily English-proficient.

E.g., MR JOHN SMITH is reissued as:
MRJOHN SMITH or MRSMITH JOHN and the staff (or even border types) reviewing docs., don't see a name match.

If your name is JOHN SMITH, stick to JOHN SMITH.