How do I stop my water pipes from making noise?

Recently I had a leak in my water lines coming from my water meter to my home. After repairing the leak, I noticed a loud drumming in my walls when ever I run water from any of my faucets. My plumber says its air in the pipes, that I should run all my water faucets at once and it will stop in time. Its been several days now and the drumming in the walls continues. What can I do to fix this? Before the leak there was no problem.