Raise your hand if you own something that you don't "need." I'm always amazed when various people ask questions like "why does someone 'need' a 30 round magazine" or "why does someone 'need' a yacht."
The correct answer is that you don't "need" any of these things, but it's none of your business if I want them. You don't need a DVD player. You don't need shoes. You don't need a microwave.
Instead of talking about whether or not a business can depreciate the value of their private jet we should be asking why government gets to tax that asset to begin with.
If a company wants to buy a jet/forklift/CNC machine/etc why does the government demand a piece of the action?
Instead of asking if raising taxes in a down economy will "help create jobs" we should ask why government deserves to take more of what people earn.