(husband was pilot who flew from various airports near his home and was reimbursed by employer for travel between airports, but not from home to airport flying out of; claimed deductions for travel expense from home to departure airport disallowed as personal expense; wife was schoolteacher who bought various items supposedly for her job and expensed the items; wife could have been reimbursed for the items but chose not to; fact that wife could have been reimbursed eliminated deductibility because items then deemed to be not "necessary").