Your entire time as a student is your interview process. If you work well with others, have good skills and are willing to do whatever it takes to succeed, you will distinguish yourself and ATP will no doubt hire you. Just like any company, they are always looking for good people.
As far as the advantages of being an instructor, I have posted a number of times, but thought I should re-set a few things. Two months ago, Jim Koziarski (the gentleman who runs ATP) offered to send my resume along with a recommendation to a number of airlines on my behalf.
I interviewed with Chautauqua airlines on June 10th and was informed a few days later that I had been hired to fly the ERJ. Having just started flying 2 years ago at the age of 33 with 0 hours, the only way I could have met my goal of a regional job by my 35th birthday (June 26) was by training and subsequently instructing at ATP.
Let me be very clear, Jim Koziarski wasn't asked by me to send my stuff into the airlines and had no obligation to offer -- he simply did what was in the best interest of an employee who had worked hard for his company. This support was just another example of why I truly believe that ATP is the best flight school in the country and is run by outstanding individuals. If you choose ATP as a schoool and an employer, and if you give 110% at all times, this is the kind of support and respect you can expect.