Nice try
Unfortunately there is no way to get state subsistence funding for the BA cadet scheme. BA will give you a weekly allowance (30 pounds) if at Oxford and more if you're going to W.Mich. You should be greatful that BA are funding you. there are thousands of people who would love to be in your position.
If you end up going to Oxford then there is a Barclays bank in the local high street (Kidlington) that do a special deal for Oxford students who are airline sponsored. It is basically a student loan of up to 1250, and is interest free for up to a year from finishing the course.