What about Employee C, earns $80,000/year and pays $700 /week in rent, but lives <10 min walk from the office, so incurs no commuting fees.
Then Employee D, earns $80,000/year and pays $400/week in rent and $300/week in parking, petrol and car wear and tear etc. So if Employee B gets a tax deduction for costs of getting to work (airfares, etc) ... why shouldn't Employee D as well? Yet Employee D has the same living expenses as Employee C, choosing to spend $300 on extra rent instead of transport.
There may be a case to be made for government assistance (in form of tax deduction or other assistance, such as stamp duty concessions) for the cost of relocating from a location to the where the work is located, with all sorts of adjustments in the economy, where work is does move around. However I can't see the case for providing tax deductions for those who choose to commute long distance (i.e. by air) compared to those who face a long daily commute, in turn to those who choose higher rent to avoid a long, costly daily commute.