First, consult with your accountant as everything I'm about to say could be completely WRONG. Second, start your own company or work for a company that is related in the aviation or training field. You can "write off" the expense of your training as long as it helps you in your profession for advancement or for business purposes. It can NOT have ANY flavor of recreation to it whatsoever.
You can create a company as sole proprietor, limited liability company, or you can go through the expense of incorporation. The first two can be done OVER THE PHONE with the IRS (you have to mail them the paperwork afterwards). Don't forget to register the business with your State, as well. Make sure you have separate bank accounts for your business. Simply pay for all training expenses from your business account as a legitimate expense.
Use your common sense. For example, if you work as a clerk in your day job... don't put "clerk" as your occupation on your 1040. Put "trainer" or something that is related to aviation (or training) and make sure you CAN JUSTIFY IT.
Since I am a technical trainer, it was a natural extension for me to write off 99.5% of all my training expenses. To wit, I am on a path to CFI as way to generate new revenue streams in the training arena. Keep meticulous expenses, and write notes on things that aren't clear. That will be important when you do your taxes, later.
Finally, it is best to pay an accountant to prepare your taxes. They have the programs and experience that will help detect if your return has anything that might trigger an audit. I use H&R block because they guarantee their returns and will sit by you IF you are audited (at no additional expense). Just don't deal with anyone who is hired for seasonal (tax season) help - get one of the regular staff.