Hi!
Second hand info originating from a aviation tax specialist: You can deduct ALL of your housing/lodging/food/travel expense, etc.
My personal opinions:
As an airline pilot, you are an employee subject to the transportation hour employee something or other (this is a question that my TurboTax asked me). You use all of your meal expenses, and then, if your perdiem is included in your W-4, you have to cut this amount in 1/2 as only 50% of meals are deducted. If your perdiem is not listed on your W-4, you must list it seperately, subtract the perdiem from you food costs, and then divide the remainder by half.
The crashpad/residence thing is interpretation. If you read all of the IRS stuff, you can't deduct it if you are based in one city and work there. If you are based in DTW as a pilot, do you do all of your work in DTW? Or, do you not fly all over the place while working? Do you sometimes report for work at a location other than DTW? Are you guarenteed to be permanently in DTW, or can your airline move you to another base? At our airline, some pilots have had 5+ bases in 1 year, all involuntary moves.
If you don't use an aviation tax professional, I would reccoment TurboTax (there are other computer programs). It's pretty easy to answer the TurboTax interview questions, with a lot of help if you need background/tax regs to figure out how to answer.
Good Luck!
Cliff