One friend here in Canada has a company with several employees and flies his PA-28 on business. He documents everything. The tax auditor disallowed a few flights as they were more costly than the airlines; however he went to the auditors boss and got that reversed.
These days when security adds 2-3 hours to any scheduled flight, any same day return trip on a private a/c is pretty easy to justify. Aircraft make time for the owner and allow him to do more business and make more money. Many business owners work 60 hour weeks and do not have 4-6 extra hours in the day to stand in security lineups.